Www.capitalhealth.ca 1 Formaldehyde Exposure Measurement at Capital Health

www.capitalhealth.ca 1

Formaldehyde Exposure Measurement at Capital Health


Formaldehyde - Introduction

Formaldehyde uses at Capital Health:

• Pathology

• Morgue

• Tissue preservation


Formaldehyde - Introduction

Tissue Preservation

• 10% buffered neutral formalin

• Volumes used 20 ml to 20 L


Formaldehyde-Introduction

Tissue Preservation - Pathology


Formaldehyde Exposure Limits

Alberta Occupational Health and Safety Code

• 8-hour TWA OEL- 0.75 ppm

• Protect against carcinogenicity

• Ceiling limit – 2 ppm

• Protect against irritation of eyes, nose and upper respiratory tract



College of American Pathologists and College of Physicians and Surgeons of Alberta Accreditation Requirements:

• 8-hour TWA exposure limit- 0.75 ppm

• 8-hour TWA action level – 0.5 ppm

• 15 min STEL – 2 ppm

• Must be maintained below these levels in areas of Anatomic Pathology

• After initial monitoring, further monitoring is mandated if results equal or exceed 0.5 ppm ( action level) or 2 ppm STEL



College of American Pathologists and College of Physicians and Surgeons – Cont’d

• Initial monitoring must be repeated anytime change in production, equipment, process, personnel, or control measures which may result in new or additional exposure to formaldehyde.

• Periodic monitoring is mandated only if the initial monitoring is at or exceeds 0.75 ppm (8 hour TWA) or 2 ppm ( STEL).

• If any personnel report signs or symptoms of respiratory or dermal conditions associated with formaldehyde exposure, the laboratory must promptly monitor the affected person’s exposure

• Requires that monitoring be performed in accordance with Alberta Occupational Health & Safety Act, code and Regulations.



Alberta Occupational Health and Safety Code , Part 4 Chemical Hazards, Biological Hazards and Harmful Substances 20(1):

• ‘If a person measures the airborne concentration of a harmful substance for the purposes of complying with the occupational exposure limits as required by the Code, the person must make the measurement

• (a) in accordance with the NIOSH Manual of Analytical Methods, 4th Edition (August 1994), …. including the 2nd supplement (January 15, 1998), or

• (b) using methods or procedures that are approved by the Director of Occupational Hygiene….”


Formaldehyde- Potential Exposure Incidents

What Kind of Sampling / Measurement is Needed?

• TWA( 8 hour )

• Short term (STEL)

• Ceiling limit










Formaldehyde- Measurement

What measurement method is needed to measure Ceiling Limit exposures?

• What is available?



Alberta Occupational Health and Safety Code , Part 4 Chemical Hazards, Biological Hazards and Harmful Substances 20(1):

• ‘If a person measures the airborne concentration of a harmful substance for the purposes of complying with the occupational exposure limits as required by the Code, the person must make the measurement

• (a) in accordance with the NIOSH Manual of Analytical Methods, 4th Edition (August 1994), …. including the 2nd supplement (January 15, 1998), or

• (b) using methods or procedures that are approved by the Director of Occupational Hygiene….”


Formaldehyde- NIOSH Methods

NIOSH

MethodDescription

Max.

Flow rate

(L/min.)

Min

Volume

(L)

Min TimeDetection

Limit

Minimum

Concentration

2016DNPH treated silica

gel tubes- HPLC1.5 1 40 sec 0.23 ug 0.2 ppm

2541HMP treated XAD-

2 tubes-GC0.1 1 10 min 3 ug 2.7 ppm

3500Impinger, bisulfite-

colorimetric1.0 1 1 min 2 ug 1.8 ppm

3800Extractive FTIR-

direct readingNA NA

1 min to fill

gas cell

(Miran

SapphIRe)

0.4 ppm

(10 meter

gascell)

0.4 ppm



No evaluated NIOSH methods were found suitable for Ceiling Limit formaldehyde measurement.

• Direct reading instrument must be used



Requirements of Direct Reading Instruments:

• Instrument method must be sensitive to 0.05 ppm

• Instrument must be accurate (±25% of true reading 95% of time-NIOSH/OSHA criteria)

• Instrument method must be able to take readings in as close to real time as possible (~ 10 second response time or less)

• Instrument method must be free of other interferences (formalin contains a high proportion of methanol, health care has many other background VOC’s)



Requirements of Direct Reading Instrument – Cont’d:

• Data logging capability so that Ceiling Limit exceedances can be captured, then correlated to work log

• Method must be approved by Director of Occupational Hygiene-Alberta Occupational Health and Safety



Direct Reading Instruments Available:

• Formaldemeter - poor response and interference from methanol and other oxidizable VOCs.

• CEA Instruments - very sensitive, too slow response to give real time, potential interferences.

• Miran sapphIRe - 1 minute cell fill time, not real time instrument, limited sensitivity, interferences.

• Detector tubes (Dragar, Gastec)- too slow response to give real time, poor sensitivity


Formaldehyde- Interscan



Literature Review References for Interscan Instrument:

• Liu,F et al reported no statistical difference between Interscan 4160 and a phenol reagent method (J. Env. Health., Vol 20, No.2, 2003.)

• NCASI Technical Bulletin 579 Laboratory and Field Evaluation of a Portable Continuous Analyzer for Measurement of Formaldehyde in Workplace Atmospheres

• 0.3 - 8 ppm - mean difference was 3.5%, coeff. var. 0.01-0.06



Literature Review References for Interscan Instrument Cont’d:

• NIOSH procedure RCT-APR-STP-0039, Determination of Formaldehyde Service Test Life, Air Purifying Respirators Standard Testing Procedure

• Mentions Interscan to give “real” time numbers in order to determine when formaldehyde breakthrough occurs in air purifying cartridges.



Literature Review References for Interscan Instrument Cont’d:

• US EPA Final Report IE 2814 Residential Indoor Air Formaldehyde Testing Program: Pilot Study

• Used Interscan for real time formaldehyde measurements in conjunction with integrated sampling methods for building material off-gassing testing.

• US EPA Method 21 Determination of Volatile Organic Compound Leaks

• Gives specifications and performance criteria of direct reading instruments used in leak detection.



Method of function

Electro-chemical voltametric sensor

Electro-catalytic sensing electrode

Sample pumped into instrument , then diffuses across medium to

electrode

Sensor electrolyte immobilized similar to electrolyte in alkaline batteries

No problem with leakage, orientation of sensor, sensor noise

Sealed reservoir eliminates reference electrode contamination

Very linear response allows single point calibration over wide range



Sensitivity

• -0.1 ppm

Accuracy

• - 0.3 -8 ppm- mean difference was 3.5%, coeff. var. 0.01-0.06

Real Time Response?

• Almost immediate, <5 seconds

Interferences?

• Minimal to other VOC’s and alcohols, instrument drift reported



Data Logging Capability?

• Yes - with external data logger (ACR Systems SmartReader7)

Approved by Director of Industrial Hygiene?

• No

• Request to Alberta Human Resources and Employment for approval of Interscan 4000 series for formaldehyde-Sep/06

• Dec / 06 approval granted with conditions:


Formaldehyde Interscan Approval

• Conditions:

• Specific to Capital Health facilities

• Normal calibration is done at least quarterly when performing according to specifications within 35-65% RH.

• Recalibration required on regular basis when RH outside 35-65%

• Regular replacement of sensor due to reports of drift (manufacturer recommends quarterly or calibration check).


Formaldehyde- Interscan Test Trial

• Calibration performed at ALS Laboratories.

• 1 m3 stainless steel calibration chamber

• Paraformaldehyde powder diluted with inert silica powder, preweighed amounts heated to vaporize formaldehyde in chamber.

• Formaldehyde concentrations measured by variety of methods.


Formaldehyde- Interscan Test Trial

• Formaldehyde concentrations measured by variety of methods:

• NIOSH 2016- DNPH treated silica gel tube--HPLC analysis

• NIOSH 3500- Impinger/bisulfite-chromotropic acid-colorimetry.

• Interscan 4000

• Miran SapphIRe


Formaldehyde-Interscan Test Trial

Form aldehyde Method Com parison

0

0.5

1

1.5

2

2.5

3

3.5

4

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Obtained concentration (ppm)

NIOSH 2016NIOSH 3500Interscan-adjustedMiran


Formaldehyde- Survey Results

• Location- Anatomical Pathology Lab- specimen preparation/ grossing.

• Workers- 2 histology technicians, one pathology assistant

• Samples collected-

• Six 8 hour TWA samples on each worker –

• NIOSH 2016- DNPH treated silica gel/ HPLC analysis

• Random / as-needed Ceiling Limit samples using Interscan 4000


Formaldehyde- Survey Results

TWA Sample Results

Description Sample Time (min.) Air Concentration (ppm)

Pathology Assistant 367 0.051

Histology Technician 456 0.11

Histology Technician 414 0.030

Area- specimen receiving 473 / 474 0.017 / 0.02

Area- grossing 471 0.02

Area- specimen storage 471 0.11


Formaldehyde- Survey Results- GROSSING

Ceiling / Activity Specific Instantaneous Interscan Readings

Description Ventilation Type Air Concentration (ppm)

Grossing very large specimen Local hood 0.050, 0.070, 0.070

Placing large specimen back

into storage bucketLocal hood 0.100

Grossing smaller specimen Local hood 0.065

Returning specimen to

container on floorGeneral ventilation 0.080

Removing fixed specimen from

containerLocal hood 0.04





Grossing medium sample Local hood0.045, 0.050, 0.060, 0.050,

0.070

Returning medium sample to

container-some splashingLocal hood 0.120

Grossing smaller specimen Local hood 0.040, 0.045

Dumpling formalin into waste

containerGeneral ventilation 0.065

Removing fixed specimen from






Removing medium sample from


Grossing medium specimen Local hood 0.060

Opening specimen transport

box- some formalin spillageGeneral only 1.60

Removing endoscopy samples

from plastic bagsGeneral only 0.40, 0.65

Over garbage can (above

plastic bags disposed of here)General only 1.10, 0.45


Formaldehyde- Results- AUTOPSY SUITE



Specimen disposal General only 0.80, 1.60, >1.99

Over open bucket of discarded

used specimensGeneral only 1.10

Room background- middle of

autopsy suite, door closedGeneral only 0.25

Addition of formaldehyde

neutralizer and stirring to neutralize

waste

General only 0.45


Formaldehyde- Results- AUTOPSY SUITE



Over open bucket of waste formalin General only <1.99

Over open bucket of ‘deformalized’

formalinGeneral only 0.90

In specimen storage room-door

openGeneral only 0.20

In specimen storage room-after

door closed 1 minuteGeneral only 0.45



Discussion:

• Interscan gave reliable, real-time information for formaldehyde concentrations

• TWA average samples indicated that average concentration was well below OEL’s

• However, Interscan identified activities/ tasks that exceeded or had potential to exceed Ceiling Limit OEL-

• very variable readings

• most likely log normally distributed with high standard deviation- highly skewed istribution



Discussion Cont’d:

• Added benefit:

• worker is shown in real time the consequences of performing certain activities,

• can make practice improvements

• can immediately reassess changes in exposures from performing improved procedures

• this is important in reducing exposures through education on chemical handling with Ceiling Limit OELs.


Acknowledgements

• Craig Hrynchuk - Senior Manager, Regional Occupational Health, Safety and Wellness, Capital Health Authority

• Chris Sheppard – Safety & Hygiene Consultant (formerly of Capital Health)

• Doug Linman - Safety & Hygiene Consultant



Questions?

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Www.capitalhealth.ca 1 Formaldehyde Exposure Measurement at Capital Health