UNIt 14 Chemical & Biological Health Hazards & Controls (Cont.) recovered.doc

Lesson:- Chemical & Biological Health Hazards & Controls (Cont

UNIT 14

Chemical & Biological Health Hazards & Controls (Cont.)


1.13 Control measures

As Paracelsus said, it is the dose that makes the poison. The purpose of the risk assessment is to quantify the dose in order to establish whether the substance is indeed a poison. The risk assessment process involves the steps of recognition, assessment and control of the risk. These will be reviewed and discussed further in this unit. A systematic approach to identifying hazardous substances is necessary in order to identify all the substances within the workplace that are hazardous. Hazardous substances can occur in the form of solids, liquids, gases, vapours, dusts, mists, or fumes. One must therefore be alert to the presence of any of these forms in the workplace. Key steps to identify hazardous substances.The following steps will provide a useful guide. Check hazardous substances registers, stock lists and inventories. Check all locations where substances are used or stored. This is particularly important where substances are not purchased through a central point such as a purchasing officer. Identify any substances that may be produced during work processes. Intermediate wastes, by-products, residues and fugitive emissions should be listed. Identify substances that are used in, or are produced by, ancillary work such as maintenance, repair, cleaning or testing. Obtain information about the substances. Consult MSDS, labels and other information sources. Identify substances that are hazardous. 1.13.1 Control measures (cont.)Recognition - The Walk-Through Survey. As a means of making a preliminary investigation into potential exposure problems, the walk through survey is a good first step in the consideration of the substances and processes involved. This is essential in recognising the hazards. The components of such a survey would include - The process: the personnel likely to be exposed and their behaviour and their comments; the substances used, handled or produced; evidence of reactions, including energy inputs/outputs; controls in place - isolation, engineering, administrative; observation of general housekeeping conditions; Workplace facilities for washing, eating, drinking, etc. sensory information - noise, odours, visible dust or mist; personal protective clothing & equipment - type and patterns of use; In addition to the above, certain further information will be useful, including:

process flow charts or diagrams; inventory of substances; records of first-aid treatments, incident and accident statistics; production and other logs; verbal information from relevant personnel; To facilitate the walk-through survey, it helps to break up the process into small sub-processes. For example, in chemical manufacturing industry, one would consider all the above points at each of the following steps:

research & development; raw materials inwards; processing & handling; packaging; storage; transport; distribution; utilisation or consumption of product; waste management, disposal or recycling. Other Factors.

When assessing the risk from exposure to a substance, it should be recognised that some persons may be more vulnerable than others, due to the influence of certain factors such as: sex; age; predisposing medical conditions; time (of day/year). 1.13.2 Control measures (cont.)

Assessment - Preliminary AssessmentWhen assessing the risk of exposure to the worker from the hazardous substance in question, a number of factors need to be considered by way of a preliminary assessment:

physical nature of the contaminant - this may be solid, liquid or an aerosol; toxicity of the contaminant; quantity of the hazardous substance present; number of people with potential for exposure; likelihood of exposure. Air Sampling.

Where a preliminary assessment indicates a potential for exposure, the next step is to quantify this level of exposure in order to establish whether the exposure is acceptable.

This may be done by sampling the air that the worker inhales to determine an indication of the level of exposure, or by taking biological samples to determine the actual level of exposure.

Air sampling of the workplace atmosphere may be done by means of static samplers to obtain a general or area sample, or it may be done by means of a personal sample, which is collected within the breathing zone of the worker. This is usually collected with the worker using a personal monitor. For the purpose of ensuring that the sample is genuinely representative of the worker's exposure, a sampling strategy must be developed to encompass a number of factors:

collection techniques; analytical techniques; where to sample; whom to sample; when to sample; how long to sample; how many samples to collect; required accuracy and precision. Following analysis, a result of the exposure concentration is found and is usually expressed as the quantity of contaminant for a given volume of air; for example, mg/m3, ppm or f/mL (fibres per millilitre) This figure is also expressed as a Time Weighted Average (TWA) for the entire period of the time of sampling. Ideally, this period should be the full time in which the worker is potentially exposed, i.e. the full length of the shift.

Compare Results to Exposure StandardIn an ideal world, there would be no exposure. Failing this, exposures should be as low as is reasonably achievable, sometimes referred to as the ALARA principle. To determine whether the level of exposure is acceptable, the result should be compared against the exposure standard for the contaminant in question. Exposure standards will be covered in a unit elsewhere, so for the purposes of this unit, it is enough to note that they are provided as a means of determining whether or not it is appropriate to employ some method of controlling the exposure. Exposure standards are not intended to indicate a 'safe/unsafe' level of exposure, nor should they be taken to indicate any adverse health effect to the worker. Control.

When exposure monitoring indicates unsatisfactory levels of exposure may be occurring, then this must be reduced. While there are various ways in which this may be achieved, a hierarchy of controls has been established, listing methods in their order of effectiveness. 1.13.3 Control measures (cont.)Methods of controlling exposureIf it is necessary to control exposure (because prevention is not practicable), it is more effective to do this by process-related means (changing aspects of the process or using engineering controls) rather than by methods which rely on personnel (e.g. personal protection). A series of 3 flowcharts supporting the following guidance are given at Figures 1 to 3 below.

The number one principle is by:

Elimination - if a hazard exists, then the most appropriate control is to eliminate it completely by not using a particular substance. For example, it may be possible to eliminate the use of chemical adhesives by fastening items together with screws or nails. Process-related methods

These may include:

Substitution when it is not possible to eliminate the use of a chemical substance, it may be possible to use a safer alternative, for example, using a water-based paint instead of a solvent-based paint. Use a different form of the same substance (e.g. purchase of solution rather than preparation from a powder, use of pellets rather than a powder). Process changes use plant, processes or systems of work which minimise the generation of hazardous substances. There are many examples of this, such as brush painting instead of spray painting, floating plastic balls (croffles) on top of liquid treatment tanks to reduce evaporation, use minimum quantities, replace lids on tins. Dust-free cleaning methods should be used (never use compressed air; use a vacuum cleaner or wet methods instead of dry sweeping). Safe storage should also be provided for hazardous substances and waste products. Isolation

the exposure may be reduced by the use of a substance in an area which is remote to the rest of the workplace (isolation by distance) or by carrying out a process during quiet hours when the fewest people are likely to be exposed (isolation by time).

Reduction of numbers of employees exposed to contaminants from a process and exclusion of non-essential access (e.g. welding, diptank areas). Reduction in period of exposure (e.g. by job rotation - this is significant for time-weighted averages). Enclosure of hazards - totally enclose (segregation) the process, preferably keeping it under slight negative pressure (e.g. glove boxes, shot blast cabinets). Alternatively, provide the operators with a clean control room, to separate them from the hazard. Biological agents should be controlled by reference to Containment Levels. Partial enclosure with Local Exhaust Ventilation (LEV) (e.g. fume cupboards, microbiological safety cabinets). Engineering methods

A process may be modified in such a way to minimise the release of aerosols, for example, by enclosure or by means of local extraction ventilation systems. This may be fixed to a machine (e.g. lip ventilation at tanks, LEV at woodworking machines) or under the control of the operator (e.g. welding fume controls). If LEV is to work effectively, it must be designed correctly. This often means that specialist advice should be obtained from an occupational hygienist or environmental health officer regarding the general design, the air velocity required and the requirement for make-up air. When using adjustable LEV (e.g. when welding), the standard of control of the contaminant will depend on the user positioning the exhaust inlet correctly. LEV must also be checked frequently and maintained, examined and tested regularly. Sufficient general ventilation (also known as dilution ventilation): This may include forced ventilation. General ventilation dilutes the contaminant rather than removing it from near its source, so it can only be effective in controlling exposure if the contaminant is of low toxicity, and is present at low concentrations or if the emissions are not near people. It may also be useful to mop up a contaminant which has escaped an LEV system. It will not be effective in controlling exposure to more toxic substances because the worker will have been exposed to them before dilution takes place. A simple analogy is when we decorate at home and paint the walls, we usually have the doors and windows open. Respiratory protective equipment (RPE): The purpose of RPE is to ensure that the wearer is provided with air which is safe to breathe. Requirements for RPE depend upon the nature of the contaminant (gas, vapour, fume or dust), its concentration in the air being breathed and the exposure limit for the substances present. Respiratory protective equipment using filters is normally sufficient to protect against particles (fumes and dust). Where asphyxiation is possible from breathing the contaminated air within the work area, or there are high concentrations of particle and/or gaseous contaminants, there is a need for RPE which provides air from an independent source.

Factors to be taken into account in the selection of RPE devices include:

The environment - is it contaminated or is it oxygen-deficient? Level of protection required. Compatibility with other protective equipment that might be required, for example safety goggles, hearing protection or oversuits. Is the wearer medically fit? Effectiveness of the fit of the RPE on the workers face; the effects of beards, spectacles, jewellery. Can the selected RPE be maintained effectively? The wearer must be trained in wearing the protection and in checking that it is working; they must fully appreciate the consequences of removing the RPE. This latter point is very important: removing protection, even for short periods to reduce discomfort or wipe the brow, can seriously compromise the overall protection achieved against, for example toxic fume or airborne particulates.Factors to be taken into account in the selection of RPE devices include

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1.13.4 Control measures (cont.)

Maintenance of RPEMaintenance is a requirement of regulation 9 of CoSHH, as is the requirement for maintenance of other control systems, such as LEV, personal protective equipment in general and RPE in particular. These need to be stored in hygienic conditions and examined and tested:

visual inspection - regularly thorough examination and testing (as appropriate) at least once a month A record of each thorough examination and test carried out should be kept and include the following details:

Particulars of the RPE and its distinguishing mark, together with a description sufficient to identify it, and the name of the maker. Date of examination and authentication of person carrying out examination and test. Condition of the equipment and particulars of any defect found (i.e. condition of filters; pressure of cylinders; volume, flow and quality of air to airline-fed apparatus).

Testing all types of RPE, but especially breathing apparatus or air fed equipment requires training in order to be competent. Manufacturers provide plenty of guidance on individual types of equipment and spare parts are generally available.

RPE must be selected on the basis of its protection performance, with respect to the multiple of the Occupational Exposure Standard (OES) individuals are being exposed to in the workplace. The main types of RPE available include:

Disposable filtering face piece respirator. Half mask respirator (Filter classification). Full mask respirator (Filter classification). Powered respirators with helmets or hoods. Powered respirators with full facemasks. Respiratory protective equipment can be divided into two major classes, according to the basic principle by which protection is given to the wearer. The two classes are

Equipment such as face masks with filters and powered respirators, which take in contaminated air from the workplace and filter or clean it before it is inhaled. All such devices are called respirators. Equipment such as air-fed hoods and self-contained breathing apparatus, which deliver uncontaminated air from an independent source to the wearer. Personal protective equipment (PPE).This should normally be regarded as a last resort (particularly in the case of carcinogens) for many reasons, but mainly because it does not prevent/reduce the spread of the contaminant and because people do not always choose to wear it correctly. It may however be used as a temporary measure until engineering controls have been installed, during maintenance work or for entry to confined spaces. Types of PPE include protective gloves, goggles, visors, aprons, overalls, Wellington boots and respiratory protective equipment (RPE).

Personal and General Environmental HygieneThe personal cleanliness of workers and their general environment is a very important factor in occupational hygiene control. Keeping clean, both in body and in clothing, is very good for personal morale and a sense of well-being. Such an attitude of mind is good for people and should help them to work better and more efficiently, together with a well- organised process, which should provide a safer workplace. The need for control has been recognised since the early factory legislation, which required the provision of clean factory areas and adequate washing and toilet facilities. Hand in hand with personal hygiene must go good general environmental hygiene and good housekeeping, with adequate provision for waste disposal systems so that the workplace can be kept tidy. Where eating facilities are provided, they should be kept free from insects and vermin. One of the most dramatic examples of limiting the incidence of occupational ill-health through personal hygiene is the case of scrotal cancer, where it has been shown that by particular attention to personal hygiene, the hazard can be eliminated. Many of the earlier cases of scrotal cancer occurred among men who did not have a bath in their homes. (It is still a problem for the drivers of diesel powered vehicles.)

Health surveillance.This may also be required in order to check whether personnel are being affected by exposure to hazardous substances. Advice on whether health surveillance is required should be obtained from an Occupational Health Adviser (doctor or nurse) or through a safety adviser.

Health surveillance will always include keeping individual health records and a range of procedures:

Biological monitoring: measurement and assessment of workplace agents or their metabolites, either in tissues, secretation or expired air, or any combination of them in exposed workers. Biological effect monitoring: measurement and assessment of early biological effects in exposed workers. Medical surveillance: clinical examinations and measurements of physiological and psychological effects of exposure to hazardous substances in the workplace, as indicated by alterations in body function. Enquiries about symptoms; inspection or examination by a suitably qualified person (e.g. an occupational health nurse). Inspection by a responsible person (e.g. chrome ulceration by a supervisor or manager). Review of records and occupational history during and after exposure, to check correctness of assessment of risks to health and to indicate if the assessment needs reviewing. Vaccines against occupational diseases may include: Sewage workers: Hepatitis A, typhoid vaccine. Construction workers: Tetanus Toxoid. Sex workers: Hepatitis A, B vaccine. Airline cabin crew: Influenza, meningitis vaccine. Food industry: Hepatitis A, typhoid vaccine. Research laboratory workers: Yellow fever, polio, rabies, hepatitis A, B, typhoid, cholera, BCG vaccine, as the case may be. Morticians, embalmers: Hepatitis B vaccine. Tattooists, acupuncturists: Hepatitis B vaccine. Where there is a risk from a needle stick injury. See Below. Hepatitis B vaccine.1.13.5 Control measures (cont.)

Locations where needles and syringes have been found include:

Parks. Public Buildings. Playgrounds. Recreation areas. In litter. Litter bins. Sink U-bends. Bags of rubbish. Hedgerows. Public toilets. Drains. Letter box baskets. Ducting. Lift shafts.

They have also been found concealed in: Cigarette packets. Toilet cisterns. Sweet papers. Bedding and clothing. Drinks cans. Undergrowth. Car seats.

Certain groups of employees may be more likely to encounter potentially contaminated needles and syringes when carrying out their normal duties. These groups include: Street cleaners. Cleaners. Caretakers. Grounds maintenance personnel. Security personnel. Park rangers.

Other control methods. Administrative methodsThis could include the development of standard operating procedures to limit exposures, or by restricting access to areas of high exposure. Specify maximum acceptable concentration of impurities (e.g. free crystalline silica in refractory materials and cements, n-hexane in some solvents). Advice on this may be obtained from manufacturers, technical sponsors and health and safety advisers. Personnel-related methods.

All personnel who may be exposed to substances hazardous to health should be provided with sufficient information, instruction and training about their work so that they can undertake it safely.

Personnel-related controls may be used in conjunction with process controls, to reduce exposure further. These may include:

Reduction of numbers of employees exposed to contaminants from a process and exclusion of non-essential access (e.g. welding, dip tank areas). Reduction in period of exposure (e.g. by job rotation). Prohibition of smoking, eating, drinking, chewing gum in contaminated areas. Provision of adequate facilities for washing, changing and storage of clothing, (including arrangements for laundering contaminated clothing) and ensuring that personnel use them. Good housekeeping is a cheap and cost-effective method of helping in the control of exposure to hazardous substances. This includes regular cleaning of spillages etc., so as to reduce airborne contamination from evaporating liquids or rising of dust from surfaces. Dust-free cleaning methods should be used. Containers should be closed when not in use, brushes should be cleaned before storing them and contaminated rags should be kept in air-tight containers.1.13.6 Control measures (cont.)Figure 1 Flow Diagram for Controlling Exposure

Figure 2 Flow Diagram for Controlling Exposure (Cont from Fig 1)

Figure 3 Flow Diagram for Controlling Exposure (Cont from Fig 2)

1.13.7 Control measures (cont.)

To recap, the hierarchy of controls (from the NEBOSH syllabus) is elimination; substitution; process changes; reduced time exposure; enclosure of hazards; segregation of process and people; local exhaust ventilation; use and limitations of dilution ventilation; respiratory protective equipment; other protective equipment and clothing (gloves, overalls, eye protection); personal hygiene and protection (e.g. vaccination) regimes; Health surveillance.Ensuring that controls continue to be effective.

All control measures must be maintained, examined and tested and they define maintenance for this context. Maintenance means any work carried out to sustain the efficiency of control measures, not just work carried out by maintenance workers, and includes visual checks, inspection, testing, preventative servicing and remedial work.

Passive control measures such as barriers should also be checked weekly and faults rectified as soon as they are found. Administrative controls, such as safe working procedures should be periodically reviewed while measures such as signs and warning notices should be checked regularly.

Preventative servicing procedures should specify which engineering controls require servicing, the nature of the servicing and the timing of the servicing. The procedures should also specify who is responsible and how any defects should be put right.

All engineering controls should receive a visual check at least once every week. All Local Exhaust Ventilation systems should be thoroughly examined and tested periodically (e.g. every fourteen months)

Personal protective equipment should be checked before each use by the operator and any defects reported. Line managers should regularly check items such as gloves, goggles and aprons.

Whatever method of control is employed, whether singly or in combination, it is important to check that it is functioning effectively by regularly monitoring the workplace environment. Analysis of data from monitoring, particularly of trends, may indicate that maintenance is required, or that workers need further training in the use of the control methods.

Employees have responsibilities to use control measures where they are provided (and use them properly). They must store PPE properly and remove it before eating, drinking and smoking. They must practice a high standard of personal hygiene and make use of the facilities provided, and they must report any defects in control measures promptly. Any employer or employee who fails to do any of the things required is likely to be in breach of the criminal law. Modern Task Ventilation

15th. Century Mining Ventilation From De Re Metallica 1.13.8 Control measures (cont.)

Record keepingWhen handling hazardous substances, it is good practice and a legal obligation to keep detailed records. As the effects of exposure to hazardous substances may not manifest themselves for many years, or may manifest themselves in the offspring of the exposed persons, it is also important that these records should be kept for at least 40 years. It does not matter in what the form the records are kept, whether on paper or in electronic format, as long as they are accessible by persons who may be exposed, or by the authorities. The only exception to this is confidential medical records. As a minimum, the records should include: the workplace chemical register including Material Safety Data Sheets; assessment reports; monitoring data; health surveillance reports; and Training records. Suitable records need to be kept for, LEV Plant Maintenance, Examination and Test Records. Some tests require specialist measurement and the local maintenance authority should be capable of conducting them on request. The results of visual inspections should also be recorded even if there is nothing wrong. Records of examinations, tests, and repair work carried out should be kept (in full detail) for at least five years. 1.13.9 LEVs

Local exhaust ventilation (LEV)

The NEBOSH syllabus requires candidates to have specific knowledge regarding LEVs namely: general applications and principles of capture and removal of hazardous substances; the components of a basic system and the factors that may reduce its effectiveness; requirements for inspection (we have already covered the latter above). Proper use of Local Exhaust Ventilation.

Operations -such as grinding, welding, handling, drying certain resin types, opening, surface defects on parts - can also release contaminants that may be harmful or cause nuisance dusts. These may release gases, vapours or fumes that may be harmful to health or create undesirable odours.

The most effective way to control these emissions is to capture them at the point of release and remove them by exhaust ventilation before they are dispersed into the air you may breathe. This capture technique is called local exhaust ventilation (LEV).

The reasons that LEVs are so effective are: only a relatively small volume of air is required to capture and remove airborne contaminants released at a point source, compared to the very large volumes required to try to change the air in an entire area of a building, and capture of contaminants at the source point can virtually eliminate any exposure of workers to the contaminants. Some principles to follow in using LEVs.

The LEV system is made up of an exhaust fan, which pulls air and contaminants into the exhaust hood and through the ducting and an air cleaner, before exhausting air outdoors (see illustration above).

REMEMBER: The hood should be as close to the source as is practical. Tests have shown that the air velocity diminishes rapidly as the distance from the hood opening is increased (see sketch below).

The hood should be shaped to enclose the source as far as is practical yet still allow access to the equipment for normal operation. The hood should be removable or connected to an adjustable duct that can be moved aside from extrusion or moulding equipment for maintenance or trouble-shooting. Adjustable ducting of this type is commercially available. Care should be taken to avoid kinking or excessive length of flexible tubing.

When exhaust air enters the hood, it will carry contaminants with it and convey them through the ducting and air cleaner to the fan and the exhaust point. The air velocity (speed) at the point where contaminants are released should usually be at least 0.5 metres per second. This is termed capture velocity, that is the air velocity that will capture contaminants at the source and pull them into the hood.

This capture velocity can be measured with a special flow meter as shown above.

The hood is the most critical part of the LEV system and a simple check of its effectiveness can be made by using a ventilation smoke tube to produce a stream of dense white chemical smoke at the location where contaminants are released. The smoke will follow the air flow and should be rapidly captured (within 1-2 seconds) by the exhaust air and swept into the hood (see below).

1.13.10 LEVs (cont.)If smoke escapes the hood and moves into the surrounding air, then some adjustment of hood location and/or air velocity will be needed. Additional enclosure around the hood may also be considered, for example, by adding heavy plastic strip curtains (see below).

Note: keep plastic curtains away from hot surfaces. High temperatures cause the plastic to become brittle and discoloured. The capture effectiveness of a hood can be improved by using flanges (see Components of LEV System sketch). The flanges restrict airflow from behind and from the sides of the hood and maximise airflow from the front.

Materials released from extruder barrel vents should be captured by LEV. Air cross-currents around the area where contaminants are generated can disperse the contaminants into surrounding air before they are captured by the hood. Portable fans, open windows or air from ceiling diffusers can cause cross-drafts which interfere with the LEV system. You can improve this situation by shielding the operation from cross-currents, for example, by using a partial enclosure with plastic strip curtains. Never locate portable fans so that air flows over hot polymer towards workers. Air should always carry contaminants away from workers. If the contaminants contain dusts, mists or fumes, the air velocity in the ducting must be high enough to prevent these materials from settling out in the ducting typically in the range 12,5 25 m/s. The product Material Safety Data Sheet will provide information on the contaminants expected to be produced during processing or thermal decomposition.

Airflow in LEV ducting can vary, for example, with changes in fan operation, plugging of filters in air cleaners, build-up of deposits in the ducting, addition of extra branches and hoods to the LEV system, etc. A simple way to monitor the system performance, once it is working properly, is to install a gauge to measure the static pressure in the exhaust duct. Workers can check the gauge for changes in static pressure in either direction which mean that the airflow has changed and, therefore, a maintenance check of the fan, duct or air cleaner is needed. Periodic checks with a smoke tube near the hood inlet will also indicate significant airflow changes. Air discharged outdoors must comply with any applicable regulations or permits for acceptable concentrations of chemical contaminants. As a responsible practice, it is recommended that exhaust air be treated by an air-cleaning device to remove all or most of the contaminant gases, vapours, dusts, mists or fumes present in the air, before discharge. Locate the exhaust stack as far away from air intakes as possible. A distance of 15 metres is usually considered to be adequate. An LEV system will only work effectively when sufficient make-up or supply air is brought into the building to replace that exhausted outdoors. This is a particular concern when LEV systems are retrofitted in cold climates requiring indoor heating. 1.13.11 LEVs (cont.)Use of portable equipment

For such applications as small-scale grinding or trim removal on plastics parts, a commercially available, portable LEV unit may be satisfactory. These units are available in various sizes and incorporate a fan, air cleaner, ducting and an exhaust hood to capture contaminants and remove them before exhausting the cleaned air back into the workplace. Such units can be recommended for capture and removal of low-toxicity dusts from plastic parts. In cases where toxic or irritating gases or vapours are released, it is important to ensure that the air cleaning device is the correct type to remove the contaminants, so that the exhaust air can be safely returned to the operating area (see illustration below). If there is uncertainty about air cleaning effectiveness, the exhaust air should be vented outside.

All Local Exhaust Ventilation systems should be thoroughly examined and tested at least once every _____ months

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1.13.12 Control measures for some aforementioned Biological Hazards

Control measures for some aforementioned Biological Hazards.

Health problems should be diagnosed quickly and regular checks should be carried out by someone who has had proper training and has access to relevant information. Early diagnosis is necessary for proper treatment and for effective prevention of recurrence. Zoonoses and Control Strategies.

Zoonoses are animal infections which may be transmitted to people in the course of their work. Transmission may be via breaks in the skin, inhalation of contaminated dust, ingestion via hands or absorption by contact with the eyes. Control may be: at source (sterilization); personal (personal protection, hygiene, system of work); of the disease (immunization, antibody testing).Legionnaires' Disease.

Type of pneumonia caused by inhalation of bacterially-contaminated water droplets. The organism thrives in stagnant water systems at tepid (25-45C) temperatures. Water systems at risk are cooling towers, systems generating sprays and those at premises with susceptible occupants (health care premises). Control is through water system treatment to avoid bacterial proliferation.Sick Building Syndrome.

Symptoms of ear, nose and throat irritations, respiratory infections, lethargy, headaches in air conditioned premises where:

occupants have little control over environmental conditions; cause is complex and may involve airborne contaminants, humidity or ventilation problems. control is through:- removal/replacement of source; isolation of source; monitoring; maintenance of ventilation systems; application of general ventilation; hygiene. Weil's Disease. Infectious jaundice caused by an organism present in the urine of rats and other animalswhich can contaminate water. Persons at risk include canal workers, sewer workers, abattoir workers. Control is through destruction of rats in infested areas, immunization, personal protection and hygiene. Hepatitis/AIDS. Both are caused by contact with infected body fluids and therefore affect health care workers and also community, custodial and emergency service personnel. Control involves prevention of puncture wounds in the presence of body fluids, protection of existing wounds, containment and disinfection of surface contamination, and safe disposal of contaminated waste. 1.13.13 The ILO Code of PracticeThe below details are extracted from the ILO Code of Practice (the Hazardous substances section from Ambient Factors in the Workplace). 12.17.16.1. Scope. 12.17.16.1.1. This element of the unit contains additional and specific requirements and information for hazardous substances (including dusts, fumes and gases) from the ILO Code of Practice Ambient Factors in the Workplace - to help employers, workers and competent authorities apply the general principles set out in earlier units. Many of the measures described here apply to biological substances, but no attempt is made here to cover the special control measures required for infectious materials, which will be the subject of another planned ILO publication.

12.17.16.1.2. In the application of the provisions in this chapter, due consideration should be given to the fluctuations in different ambient factors that may exacerbate the adverse effects on the health of workers, the general public and the environment.

12.17.16.1.3. Where the workers are exposed to hazardous chemicals (dusts, fumes, gases), the provisions of the ILO code of practice Safety in the use of chemicals at work (Geneva,1993) should apply.

12.17.16.1.4.Exposure to hazardous substances should be kept as low as reasonable and practicable, and within the established exposure limits.

12.17.16.2. Assessment. 12.17.16.2.1. As the first stage of the assessment, the employer should inspect the workplace and obtain information on:

(a) hazardous substances that are present or likely to occur, along with other hazardous ambient factors (see paragraph 3.1.3 above); (b)

activities that take place; (c) any hazardous substances or processes that may easily be eliminated.

12.17.16.2.2. Consideration should be given to obtaining information on:

(a)the intrinsic hazards of the raw materials, products and by-products according to the physical states (e.g. solid, liquid, gas) in which they occur or are produced;

(b) the ambient conditions (e.g. barometric pressure, temperature, etc.) under which the hazardous substances are used or produced; (c) the impact of either the change in phase of the hazardous substances (e.g. solid to liquid phase) or fluctuations in the ambient conditions on the health of workers exposed, the public and the environment.

12.17.16.2.3. In the case of chemicals, the employer should obtain information from suppliers in accordance with the provisions of Chapter 5 of the ILO code of practice Safety in the use of chemicals at work ( Geneva , 1993). Where this is not practicable, employers should obtain information provided by other bodies such as the International Agency for Research on Cancer (IARC), the International Programme on Chemical Safety (IPCS), the European Communities and other international and national institutions.

12.17.16.2.4. Where the risk is from exposure to mineral or synthetic fibres, mineral dusts and vegetable dusts, employers should consider the provisions in the Asbestos Convention (No. 162), and Recommendation (No. 172), 1986; ILO codes of practice Occupational exposure to airborne substances harmful to health (Geneva, 1980) and Safety in the use of asbestos (Geneva, 1984); the ILO guide on Safety and health in theuse of agrochemicals (Geneva, 1991); and Dust control in the working environment(silicosis) (Geneva, 1997) (ILO Occupational Safety and Health Series No. 36).

12.17.16.2.5. When obtaining information for assessment, employers should take account of specific work situations where workers are likely to be exposed, for example, to:

(a)

hazardous fumes as by-products (e.g. welding); (b) hazardous substances and/or oxygen deficiency in confined spaces; (c) prolonged periods (such as during overtime) with the risk of accumulation of higher doses;(d) higher concentrations due to fluctuations in ambient conditions (e.g. hot environments where vapour pressures of hazardous substances may be elevated); (e) absorption through multiple routes (inhalation, ingestion, absorption through the skin); (f) hazardous substances that may be present even in concentrations below exposure limits while performing arduous tasks.

12.17.16.2.6. In the situations listed above, the exposure limits specified by the competent authority for normal work situations would often be invalid.

Employers should accordingly obtain practical information from the competent authority, international organisations and institutions (ILO, WHO, IPCS) or other bodies.

12.17.16.2.7. As the second stage of the assessment, the employer should use the information obtained to assess the risk to health resulting from exposure, especially from the effects of chemical mixtures, and should also take account of:

(a)

routes of entry (skin, inhalation, ingestion); (b) the risk of penetration through damaged skin or seepage through personal protective equipment; (c) the risk of ingestion (due to personal hygiene levels and cultural variations); (d)

levels of airborne concentrations of hazardous substances; (e)

the rate at which work is performed (e.g. arduous tasks); (f) the length of exposure (e.g. higher exposures resulting from prolonged overtime); (g) the influence of other ambient factors (e.g. heat) in enhancing the risk of exposure.

12.17.16.2.8. During the third stage of the assessment, the need for a programme for the measurement of airborne contaminants should be determined. It should be based on the information listed in paragraphs above. It may also be preceded by simple qualitative tests such as the use of smoke tubes to determine ventilation characteristics, and the use of dust lamps for dust emissions. Such a programme is required to:

(a)

determine the extent of exposure of workers; and/or (b)

check the effectiveness of engineering control measures.

12.17.16.2.9. The monitoring of airborne contaminants should be performed only by persons technically competent to:

(a)determine the compatibility of sampling equipment with available analytical methods and validate the results;

(b) interpret the results of monitoring with due regard to information obtained through the provisions within this unit, and with reference to exposure limits or other criteria determined by the competent authority. 12.17.16.2.10. The employer should:

(a) arrange for regular inspection, maintenance and proper calibration of monitoring equipment;

(b) review the assessment as specified in units of this eLearning course.

12.17.16.2.11. Employers should keep dated records of measurements of airborne contaminants by technique and type (e.g. static, personal), including data on plant location, work area, work processes, nature of hazardous substances, names and lists of exposed workers and control measures in place. Such records should be kept for a period to be determined by the competent authority.

12.17.16.3. Prevention and control. 12.17.16.3.1. Where the assessment of hazards or risks shows that control measures are inadequate or likely to become inadequate, risks should be:

(a) eliminated by ceasing to use such hazardous substances or replacing them with less hazardous substances or modified processes;

(b) minimised by designing and implementing a programme of action;

(c) reduced by minimising the use of toxic substances, where feasible.

12.17.16.3.2. Control measures for implementing such a programme could include any combination of the following:

(a)

good design and installation practice:

(i) totally enclosed process and handling systems;

(ii) segregation of the hazardous process from the operators or from other processes;

(iii) plants, processes or work systems which minimise generation of, or suppress or contain hazardous dusts, fumes, etc., and which limit the area of contamination in the event of spills and leaks;

(iv) partial enclosure, with local exhaust ventilation;

(v) local exhaust ventilation;

(vi) sufficient general ventilation;

(b) work systems and practices:

(i) reduction of the numbers of workers exposed and exclusion of non-essential access;

(ii) reduction in the period of exposure of workers;

(iii) regular cleaning of contaminated walls, surfaces, etc.;

(iv) use and proper maintenance of engineering control measures;

(v) provision of means for safe storage and disposal of substances hazardous to health;

(c) Personal protection:

(i) where the above measures do not suffice, suitable personal protective equipment should be provided until such time as the risk is eliminated or minimised to a level that would not pose a threat to health;

(ii) prohibition of eating, chewing, drinking and smoking in contaminated areas;

(iii) provision of adequate facilities for washing and changing and for storage of clothing (everyday clothing separated from work clothing), including arrangements for laundering contaminated clothing;

(iv) use of signs and notices;

(v) adequate arrangements in the event of an emergency.

12.17.16.3.3. With regard to control measures for hazardous chemicals in respect of storage, transport, disposal and treatment, the provisions laid down in the ILO code of practice Safety in the use of chemicals at work (Geneva, 1993) should apply, to the extent practicable with due regard to their flammability, reactivity and explosivity.

12.17.16.3.4. Additional precautions should be taken by the employer to protect the workers against risks to safety and health presented by those hazardous substances as may be specified by the competent authorities or in the ILO Conventions, Recommendations, codes of practice and guides and other standards issued by international organisations and other bodies (see recommended reading list).

1.13.14 Health surveillance

12.17.16.4.1. The provisions of this code concerning health surveillance, the use of its results and record keeping should apply. 12.17.16.4.2. Exposure to the following types of hazardous substances may require appropriate health surveillance:

(a)

substances (dusts, fibres, solids, liquids, fumes, gases) that have a recognised systemic toxicity (i.e. an insidious poisonous effect);

(b) substances known to cause chronic effects (e.g. occupational asthma);

(c)

substances known to be sensitisers, irritants or allergens;

(d) substances that are known or suspected carcinogens, teratogens, mutagens or harmful to reproductive health (reprotoxic substances);

(e) other substances likely to have adverse health effects under particular work conditions or in case of fluctuations in ambient conditions.

12.17.16.4.3. In the case of exposure of workers to specific hazards, health surveillance should include biological monitoring for the early detection of the effects on health when:

(a)

a valid and generally accepted reference method exists;

(b) it may be used to identify workers who need detailed medical examination (subject to the individual worker's consent);

(c) it may be necessary to detect exposure levels and early biological effects and responses.

1.13.15 Training and information

12.17.16.5.1. Employers should ensure that workers have sufficient, specific and systematic training and information on:

(a) the nature and degree of hazards and risks from hazardous substances which may occur, particularly in the case of an emergency;

(b) the protection of their safety and health and that of others from hazardous substances which may be present, in particular by using correct and prescribed methods for the handling, storage and transport of hazardous substances, and waste disposal;

(c) the correct and effective use of control and protection measures and of personal protective equipment.

This information should also be transmitted, where appropriate, to subcontractors and their workers.

12.17.16.5.2 Employers should ensure that special provisions for training and information are applied for newly-recruited workers and for illiterate workers or foreign workers who may encounter language difficulties.

12.17.16.5.3. Employers should inform workers and their representatives, as appropriate, of the results of workplace assessments and of their health surveillance in relation to risks caused by exposure to hazardous substances, and in particular those workers who have specific needs for protection related to their health condition.

12.17.16.5.4. Employers should ensure that their relevant managerial staff are appropriately trained so that they may thoroughly instruct the workers regarding the precautions to be taken in their jobs and in the event of emergencies.

12.17.16.5.5. In accordance with the provisions of the Chemicals Convention, 1990 (No.170), and the ILO code of practice Safety in the use of chemicals at work (Geneva,1993), the workers concerned and their representatives should be given information:

(a) on the nature of chemicals used at work, the hazardous properties and precautionary measures to be taken;

(b) in the form of labels and markings, and set out in chemical safety data sheets; in forms and languages which they easily understand.

1.13.16 Relevant UK statutory provisions & Sources of reference

Sources of reference:-

Step by Step Guide to COSHH Assessment (HSG97), HSE Books. Occupational Exposure Limits (EH40), HSE Books (updated annually). General COSHH ACoP , Carcinogens ACoP and Biological Agents ACoP (L5), HSE Books Personal Protective Equipment at Work (Guidance) (L25), HSE Books. An Introduction to Local Exhaust Ventilation (HSG37), HSE Books. The Selection, Use and Maintenance of Respiratory Protective Equipment (HSG53), HSE Books. 1.13.17 Chemical & Biological case studiesCase Study A. An MVR site was investigated because there were reports of occupational ill-health amongst workers there. Biological monitoring showed that all staff, including administrative staff who never did any painting, had been exposed to isocyanates from the spray paints in use at the factory. An investigation showed that the spray booth at the site was leaking. Isocyanates from the leaking booth were able to spread throughout the building, so everybody who worked there was exposed to them. This was an unexpected finding because the spray booth had been recently serviced, inspected and tested, and was thought to be working properly. The leaking spray booth was then repaired and further biological monitoring showed that the spray booth was working properly. However, one of the paint sprayers was still exposed to isocyanates. Further investigations revealed that he had not received proper instructions and was not using his breathing apparatus correctly. As a result, his exposure was not as low as it could have been. More here http://www.hsl.gov.uk/capabilities/mvrisocy.htm1.13.18 Summary and Conclusions

DO

Read assessment or label, use as directed.

Use only the right, issued substance.

Avoid contact or breathing mists vapours.

DO NOT

Decant into unmarked containers.

Mix substances.

Use other than as directed.

INTRODUCING A NEW SUBSTANCE Before ordering, get a MSDS sheet.

Enter the substance on the system.

Make an assessment, place controls. DO NOT

Use anything without assessment.

Instruct staff to use an unknown substance.

Disregard warnings.

DUTY OF EMPLOYERS. Assess risks to health caused by substances used at work.

Prevent or control exposure.

Ensure use of control methods.

Monitor the work environment.

Carry out health surveillance as necessary.

Provide information, instruction and training as necessary.

2.0 SummaryThis summary section will refer you back to the learning outcomes and summarise the notes.

Recognise the forms of, and classification of, substances hazardous to health

Dust:

Airborne solid particles. Dusts are generated and dispersed into the air by, for example, handling, sieving, crushing and grinding of organic or inorganic materials such as rock, ore, metal, coal, wood and grain. Particles within the size range 0.01 to 100 microns may form an aerosol. In still atmospheres, dust can tend to settle under gravity, and where dust accumulations are produced, a serious hazard in regard to a dust explosion can occur.

Fume: An aerosol of solid particles generated by condensation from the gaseous state, generally after a metal has been converted from molten metals. The solid particles that make up a fume are extremely fine, usually less than 1.0 micron in diameter. In most cases, the volatised solid reacts with oxygen in the air to form an oxide; these produce highly toxic fumes. Common examples include cadmium oxide fume, welding and lead burning.

Gas:

A formless fluid that completely occupies the space of any enclosure at the right temperature and pressure. There are many toxic gases used in industry, such as chlorine, sulphuretted hydrogen (hydrogen sulfide, H2S) etc. Many are nasal and respiratory tract irritants. This irritant factor can give rise to immediate evacuation (for example, sneezing) before too much harm is done to the tissues lining the respiratory passages.Mist:

An aerosol of suspended liquid droplets generated by condensation from the gaseous to the liquid state or by the breaking up of a liquid into a dispersed state, such as by splashing, foaming, or atomizing. Mist is formed when a finely divided liquid is suspended in the atmosphere. Examples are the oil mist produced during cutting and grinding operations, acid mists such as chromium from electroplating, acid or alkali mists from pickling operations and paint spray mist from spraying procedures.

Vapour:

The gaseous phase of a material that is liquid or solid when there is a rise in temperature which causes the vaporisation. Examples are organic solvent vapours.

Liquids:

It has been estimated that two-thirds of all industrial injuries from chemicals are skin injuries caused by direct bodily contact with liquid acids and alkalis due to the corrosive effect of these substances.

Aerosol:

A dispersion of particles of microscopic size in a gaseous medium; may be solid particles (dust, fume, smoke) or liquid particles (mist, fog).

Smoke:

An aerosol of carbon or soot particles less than 0.1 mm in diameter that results from the incomplete combustion of carbonaceous materials such as coal or oil. Smoke generally contains droplets as well as dry particles.

Fog:

A visible aerosol of a liquid, formed by condensation.

Classification of substances hazardous to health

Irritant Substances.

A substance is an irritant if it causes inflammation of the skin, eye irritation, serious eye effects or irritation to the respiratory system. Examples of Irritant Substances are: Ammonia.

Corrosive Substances.

A corrosive substance causes destruction of, or damage to, materials or living tissue on contact. Examples of Corrosive Substances are: Nitric acid, most strong acids and strong bases commonly found in cleaning chemicals.

Toxic Substances.

Toxicity is defined as the capacity of an agent to produce damage to an organism. This usually refers to functional (systemic) damage, but may be developmental in respect of tissue and skeleton in the case of the embryo. The damage may be permanent or transient. Examples of Toxic Substances are:- Pesticides, benzene in gasoline, many solvents, lead. Cyanides are highly toxic. Hydrogen cyanide was used in prison gas chambers.

Harmful Substances.

A Harmful substance presents a hazard to health which is somewhat less than that presented by a toxic or very toxic substance. You will see the description harmful on substances such as cleaning agents.

Carcinogenic Substances.

A carcinogenic substance is one which is capable of causing cancer. A cancer is a malignant tumour which can spread to other organs of the body, as distinct from a benign tumour, which cannot. Although leukaemia and some other malignant diseases are not solid tumours, they meet other criteria for cancer and can be, and often are, included under this definition. Examples of Carcinogenic Substances are:- Asbestos

Mutagenic Substances.

Mutagenic Substances interfere with the genetic control of the cell, so causing mutations. An example of Mutagenic Substance: Ethidium bromide is a strong mutagen and a possible carcinogen or teratogen. It has been used for many years in laboratories as a nucleic acid stain.

Teratogenic Substances.

Teratogenic substances are those that cause harmful effects to the unborn child. For example, alcohol is a teratogen and drinking during pregnancy can lead to a child born with foetal alcohol syndrome. Many drugs can also have an adverse effect on developing foetuses, the most infamous example being thalidomide . This drug was used to control morning sickness, but was withdrawn from the market after it was discovered to cause limb and other developmental deformities.

Asphyxiants

interfere with the body's intake of oxygen. Example of a chemical asphyxiant is carbon monoxide. Nitrogen is a simple asphyxiant.

There are also Dermatitic/Sensitising Substances

Explain the factors to be considered when undertaking a preliminary assessment of the health risks from substances commonly encountered in the workplace;

Key steps to identify hazardous substances:

The following steps will provide a useful guide.

Check hazardous substances registers, stock lists and inventories.

Check all locations where substances are used or stored. This is particularly important where substances are not purchased through a central point such as a purchasing officer.

Identify any substances that may be produced during work processes. Intermediate wastes, by-products, residues and fugitive emissions should be listed.

Identify substances that are used in, or are produced by, ancillary work such as maintenance, repair, cleaning or testing.

Obtain information about the substances. Consult MSDS, labels and other information sources.

Identify substances that are hazardous.

Control Measures

Assessment -

Preliminary Assessment:

Air Sampling: Where a preliminary assessment indicates a potential for exposure, the next step is to quantify this level of exposure in order to establish whether the exposure is acceptable.

Compare Results to Exposure Standard : To determine whether the level of exposure is acceptable, the result should be compared against the exposure standard for the contaminant in question.

Control: When exposure monitoring indicates unsatisfactory levels of exposure may be occurring, then this must be reduced. While there are various ways in which this may be achieved, a hierarchy of controls has been established, listing methods in their order of effectiveness.

Describe the use and limitations of Workplace Exposure Limits including the purpose of long term and short term exposure limits;

A fundamental requirement is that the exposure of employees to such hazardous substances should be prevented, or, where this is not reasonably practicable, adequately controlled. Exposure to harmful materials can occur by inhalation, by ingestion or by absorption through the skin but inhalation is usually the main route of entry into the body.

Where there is exposure to a substance for which a Workplace Exposure Limit (WEL) has been specified, then the control of exposure, as far as inhalation is concerned, is considered to be adequate only if

i) the use of such a substance is justified because there is no practical safer alternative and

ii)the level of exposure is reduced as far as is reasonably practicable and in any case below the WEL .

Setting Exposure Limits: Exposure limits are set as the result of deliberation of expert committees and public consultation.

For a WEL to be set, there are serious implications for the health of workers exposed to the substance. In practice, WELs have most often been assigned to carcinogens and to other substances for which no threshold of effect can be identified and for which there is no doubt about the seriousness of the effects of exposure.

When accepted, WELs are added to Schedule 1 of CoSHH and reproduced as Table 1 of the Health and Safety Executive document EH40.

Units of Measurement: For occupational exposure limits, concentrations of gases and vapours are usually expressed in parts per million (ppm), a measure of concentration by volume, as well as in milligrams per cubic metre of air (mg.m-3), a measure of concentration by mass. For airborne particles (fume, dust etc.) the units are mg.m-3 and may refer to the "total inhalable" fraction i.e. that which can enter the nose and mouth during breathing and so be deposited in the respiratory tract, or to the "respirable" fraction i.e. that which penetrates to the gas exchange region of the lungs.

Long Term and Short Term Limits: The effects due to exposure to hazardous substances depend on the nature of the substance and the length of the exposure; some effects require prolonged or accumulated exposure, whilst other effects become apparent very quickly. Long term (8-hour Time Weighted Average or TWA) exposure limits are intended to control the slower effects by restricting the total intake by inhalation over one or more work-shifts and short term exposure limits (usually 15 minutes) are applied to control more rapid effects.

Control of Exposure : WELs are designed to control the absorption into the body of harmful substances following inhalation. They are not concerned with absorption following ingestion or skin contact. Where substances can be absorbed following skin contact, a warning is given by noting this characteristic by the abbreviation "Sk" alongside the exposure limit.

Control methods are therefore concerned with limiting the amount of harm in respirable air by the use of standard control methods, e.g. local exhaust ventilation; or, where safe-place strategies cannot be created, by the use of personal protection.

The main objective in each case is to reduce personal exposure to the lowest possible level by means that are reasonably practicable. This also underlines another important factor in the implementation of WELs - that compliance is based upon the measurement of environmental contamination by the use of personal monitoring systems. A casual stroll around the workplace making a few arbitrary tests with a stain tube detector does not satisfy the HSE monitoring criteria.

Distinguish between acute and chronic health effects;

Acute conditions are of short duration and may be generally said to conclude with the recovery or the death of the patient. Carbon monoxide poisoning is an acute condition, as is Legionnaires' disease.

Chronic conditions last for longer periods - months or years. Chronic includes conditions such as tuberculosis, AIDS, hepatitis B and athletes foot - not all chronic conditions are serious. Some agents can be associated with both chronic and acute conditions: for example, the acute effect of cadmium is severe lung irritation and the chronic effects of cadmium are emphysema (lung damage) and kidney damage. Some chronic effects such as cancer can occur some 20-30 years after the exposures.

Outline control measures that should be used to reduce the risk of ill-health from exposure to hazardous substances

Methods of controlling exposure : If it is necessary to control exposure (because prevention is not practicable), it is more effective to do this by process-related means (changing aspects of the process or using engineering controls) rather than by methods, which rely on personnel (e.g. personal protection).

The number one principle is by:

Elimination

If a hazard exists, then the most appropriate control is to eliminate it completely by not using a particular substance. For example, it may be possible to eliminate the use of chemical adhesives by fastening items together with screws or nails.

Process-related methods may include:

Substitution: when it is not possible to eliminate the use of a chemical substance, it may be possible to use a safer alternative, for example, using a water-based paint instead of a solvent-based paint. Use a different form of the same substance (e.g. purchase of solution rather than preparation from a powder, use of pellets rather than a powder).

Process changes:Use plant, processes or systems of work, which minimise the generation of hazardous substances. There are many examples of this, such as brush painting instead of spray painting, floating plastic balls (croffles) on top of liquid treatment tanks to reduce evaporation, use minimum quantities, replace lids on tins. Dust-free cleaning methods should be used (never use compressed air; use a vacuum cleaner or wet methods instead of dry sweeping). Safe storage should also be provided for hazardous substances and waste products.

Isolation : The exposure may be reduced by the use of a substance in an area which is remote from the rest of the workplace (isolation by distance).

By carrying out a process during quiet hours when the fewest people are likely to be exposed (isolation by time).Reduction of numbers of employees exposed to contaminants from a process and exclusion of non-essential access (e.g. welding, diptank areas).

Reduction in period of exposure (e.g. by job rotation - this is significant for time weighted averages).

Enclosure of hazards: Totally enclose (segregation) the process, preferably keeping it under slight negative pressure (e.g. glove boxes, shot blast cabinets). Alternatively, provide the operators with a clean control room, to separate them from the hazard. Biological agents should be controlled by reference to Containment Levels. Partial enclosure with Local Exhaust Ventilation (LEV) (e.g. fume cupboards, microbiological safety cabinets).

Engineering methods: A process may be modified in such a way to minimise the release of aerosols, for example, by enclosure or by means of local extraction ventilation systems (LEV). This may be fixed to a machine (e.g. lip ventilation at tanks, LEV at woodworking machines) or under the control of the operator (e.g. welding fume controls). If LEV is to work effectively, it must be designed correctly. This often means that specialist advice should be obtained from an occupational hygienist or environmental health officer regarding the general design, the air velocity required and the requirement for make-up air. When using adjustable LEV (e.g. when welding), the standard of control of the contaminant will depend on the user positioning the exhaust inlet correctly. LEV must also be checked frequently and maintained, examined and tested regularly. LEVs continued below.

Sufficient general ventilation (also known as dilution ventilation):- This may include forced ventilation. General ventilation dilutes the contaminant rather than removing it from near its source, so it can only be effective in controlling exposure if the contaminant is of low toxicity, and is present at low concentrations or if the emissions are not near people. It may also be useful to mop up a contaminant which has escaped an LEV system. It will not be effective in controlling exposure to more toxic substances because the worker will have been exposed to them before dilution takes place. A simple analogy is when we decorate at home and paint the walls, we usually have the doors and windows open.

Respiratory protective equipment (RPE): The purpose of RPE is to ensure that the wearer is provided with air which is safe to breathe. Requirements for RPE depend upon the nature of the contaminant (gas, vapour, fume or dust), its concentration in the air being breathed and the exposure limit for the substances present. Respiratory protective equipment using filters is normally sufficient to protect against particles (fumes and dust). Where asphyxiation is possible from breathing the contaminated air within the work area, or there are high concentrations of particle and/or gaseous contaminants, there is a need for RPE which provides air from an independent source.Outline the basic requirements related to disposal of waste and effluent (and the control of atmospheric pollution).

Environmental considerations

The earliest environmental legislation in the United Kingdom dates as far back as 1863 and was aimed at controlling atmospheric emissions from the caustic-soda industry. The first major piece of legislation, however, came into force in 1974 in the form of the Control of Pollution Act (COPA).

Duty of Care: There is a duty of care on everyone dealing with waste, i.e. those who import, produce, carry, keep, treat or dispose of controlled waste. The Duty of Care is set out in section 34 of the Environmental Protection Act 1990. It applies to anyone who is the holder of controlled waste.

Controlled waste: Controlled waste means waste from households, commerce or industry. At present, the main kinds of waste that are not controlled waste are waste from agricultural premises, waste from mines and quarries, explosives and most radioactive waste.

Those subject to the duty are required to follow four requirements.

Requirement 1

It stipulates that the holder of waste ("holder" means a person who imports, produces, carries, keeps, treats, or disposes of controlled waste, or as a broker, has control of it) must take all reasonable steps to prevent its escape. Householders are exempt from the duty of care for their own household waste.

Containing your waste appropriately during storage and transportation depends on the nature of the waste and its disposal route.

Requirement 2 (Acceptance of Waste)

Under the Duty of Care, you are obliged to make sure that waste is only transferred to someone authorised to carry or manage waste - known as an authorised person.

Requirement 3

Under the Duty of Care, you are required to keep records of the waste you produce and transfer, and also to complete, sign and keep transfer notes.

A transfer note should be completed whenever waste is handed over to an authorised person and should be signed by all parties.

The waste transfer note details:

from whom and to whom the waste has been transferred;

the category of authorised person to whom the waste has been consigned;

relevant licence numbers;

time, place and date of transfer;

the quantity of waste;

how the waste is packed and in what type of container, if at all;

any special requirements that may be important to avoid risk in the waste's transport, storage, treatment or disposal;

the type of site that the waste comes from (i.e. hospital, power-station);

the name of the substance or substances;

the processes that produced the waste;

a chemical and physical analysis (where appropriate);

the names and addresses of both parties.

In addition, if your waste causes any special problems in handling or treatment, a fuller description is required comprising:

special problems related to the waste;

source of the waste;

name of the substance;

process producing the waste;

chemical and physical analysis, when appropriate.

If your waste does not cause any special problems, a simple description is generally adequate and should contain the source of the waste or the name of the substance.

Trade effluent encompasses any liquid waste or suspension of solids of any quantity that results from an organisation's operations. It can, therefore, include waste chemicals, cooling water, liquid process wastes and wash water, other than human and domestic waste.

When no site drainage plans are available, it is impossible to confirm whether these effluents are being discharged to the foul sewer, the surface water drainage system or straight to a watercourse.

Spillages and leakages are also considered to be waste and, in the event of a spillage or leakage the company may be liable.

Complying with the Rules: All hazardous materials, waste or otherwise, should be stored intact and in labelled containers. Different chemicals and wastes should be segregated for ease and safety of management.

An up-to-date drainage plan should be maintained, spillage hazards identified and a spillage contingency plan, giving advice on what action to take and who should be informed in the event of a spillage, should be drawn up.

These plans should be clearly displayed or made available to staff, and appropriate spill kits or absorbent materials should be held on site. Staff should also be trained in their use.

Note:

The materials contaminated with Hazardous Waste become Hazardous Waste themselves. Thus, cleaning rags, wipers, absorbent materials used for cleaning up spills could all be classified as Hazardous Waste.

Loading and unloading hazardous materials: Loading and unloading areas should be clearly marked and isolated from the surface water or foul sewer drainage systems, ideally by employing catch pits. Cut-off valves in the drainage system and raised kerb surrounds may also be needed, together with drainage to the foul sewer, as opposed to the surface water drainage system, where possible.


Congratulations - end of lesson reached

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