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T. Renée Anthony, PhD, CIH, CSP
Department of Occupational and Environmental HealthThe University of Iowa
Pit Foam & Producer Safety:Hazards and Prevention of Airborne Exposures and Risks
Iowa Pork CongressJanuary 27, 2016 | 10:45 – 12:00Hy-Vee Hall, Lower Level, Rooms 107 & 108
Seminar Objective Dr. Renée Anthony
Identify chronic and acute health and safety hazards associated with chemicals in swine production buildings
Discuss identification and prevention alternatives
Leon Sheets Share producer experiences of barn fire
Dr. Dan Andersen Update state of knowledge of foaming manure Discuss prevention strategies
Objectives Provide Motivation and Rationale Identify chronic health hazards in swine production
buildings Common contaminants Health risks: current state of knowledge Prevention options
Discuss acutely hazardous gases: H2S and CH4 Sources Risk factors Prevention considerations
Acknowledgements Great Plains Center for Agricultural Health
CDC/NIOSH U54 OH007548
Iowa Fatality Assessment and Control Evaluation (FACE) CDC/NIOSH 2U60OH008460-10 Subcontract with the Iowa Department of Public Health
(IDPH)
I: Chronic Health Hazards Air contaminants in swine CAFO
Ammonia (NH3) – manure pits, urine Hydrogen sulfide (H2S) – manure pits Dust (respirable, inhalable) – food, animal dander, manure Endotoxin (on dust) – animal dander, manure Carbon monoxide (CO) – heaters Carbon dioxide (CO2) – heaters, swine respiration
Workers in swine CAFO exhibit adverse health outcomes Declines in lung function (FEV1 dose-dependent) Increased prevalence of respiratory symptoms
(chronic cough, phlegm) Increased prevalence and amount of inflammation
(bronchial lavage)
Clear need to reduce exposures to these workers
Risk Factors Clear need to reduce exposures to these workers
Winter exposures are highest
Risk Factors Clear need to reduce exposures to these workers
Winter exposures are highest
O'Shaughnessy et al. (2010) A Task-specific assessment of swine worker exposure to airborne dust. Journal of Occupational and Environmental Hygiene 7(1):7-13
Inhalable Dust Endotoxin
Risk Factors Clear need to reduce exposures to these workers
Winter exposures are highest
Duchaine et al. (2000) Influence of building maintenance, environmental factors, and seasons on airborne contaminants of swine confinement buildings. AIHAJ 61(1):56-63
“Total” Dust Endotoxin Ammonia
Dust and ammonia significantly higher in winter.(Endotoxins analyzed by different methods: not comparable between seasons)
Risk Factors Clear need to reduce exposures to these workers
Winter exposures are highest
Jacobson et al. (2005) Spatial, diurnal, and seasonal variations in temperature, ammonia, and hydrogen sulfide concentrations in two tunnel ventilated sow gestation buildings in MN. Livestock Environment VII, Proceeding of 7th International Symposium 18-20 May 2005, ASAE Publication 701P0205, 198-206
Hydrogen Sulfide (Gestation)
Ammonia(Breeding)
Significant increases in winter: 100 to 1000 ppb H2S, 2-25 ppm NH3
Risk Factors Clear need to reduce exposures to these workers
Winter exposures are highest Concentrations increase over the winter
Risk Factors Clear need to reduce exposures to these workers
Winter exposures are highest Concentrations increase over the winter
Risk Factors Clear need to reduce exposures to these workers
Winter exposures are highest Concentrations increase over the winter Exposure recommendations:
Single component – OSHA, ACGIH, other… not consider combined effect to compounds associated with health outcomes
Multiple component – Literature recommendations to prevent declines in lung function and inflammation
Recommended Exposure LimitsOccupational Exposure Limits (OELs) ACGIH TLVs – Single component limits, which do not account for mixtures
Threshold
Large Dust, mg/m3
Small (Respirable) Dust, mg/m3
NH3, ppm
CO, ppm
CO2, ppm
OEL 10 3 25 25 500050% OEL 5 1.5 12.5 12.5 250010% OEL 1 0.3 2.5 2.5 500Literature recommendations:
Donham et al. 1989, 1995
2.8 (T)(<10%
decrease in FEV1)
0.237
(3% decline in FEV1)
-1540(FEV50, FEF50)
Vogelzang et al. 2000 2.6 (I) 7.2
Increased bronchial hyperresponsiveness
Methods to Reduce Exposures Focus on dust/endotoxin exposure reduction Respiratory Protection: N95 Respirators
Low Adoption: 26% of MN farmers “sometimes” used (Odu et al. 2015)
Iowa Outreach: Community college education activities (fit testing, hands-on demonstrations) – Sheridan, Rudolphi
Engineering Controls Oil mist – Zhang et al. 1996; Senthilselvan et al.
1997; Rule et al. 2005 Recirculating ventilation with dust removal
(winter) – Park et al. 2013; Anthony et al. 2014, 2015; Peters et al. 2015
Methods to Reduce Exposures Recirculating Ventilation Findings
1000 cfm (5.4 air exchanges/hour) No increased room concentrations of gases
from operation (NH3, H2S, CO, CO2) Two air control units tested in farrowing barn
Filtration (SDC) reduced particles by: 33% for large (inhalable) 41% for small (respirable)
Cyclone reduced particles by: 44% for large (inhalable) 18% for small (respirable) Filtration (SDC) Cyclone
Methods to Reduce Exposures Recirculating Ventilation Findings
Also identified high CO2 generated by common LPG heaters Unvented heater (Yr 1)
Mean: 2480 ppm (330 ppm SD)Exceeded 1540 ppm all daysMean approached ½ single gas OELs
Vented heater (Yr 2)Mean: 1401 ppm (330 ppm SD)Exceeded 1540 ppm on 5 of 19 days
800 ppm drop due to heater Between years, outdoor temperatures
and sow/piglet counts also varied
Additional Information Detailed results of heater and ventilation studies
available http://www.public-health.uiowa.edu/gpcah/center-projects/in
tervention-to-reduce-exposures-in-cafos/
Ventilation Study:
II: Acute Effects - Manure Gases High concentrations for short periods of time result in
serious health and safety hazards Hydrogen Sulfide (H2S) – In manure pit
50 – 100 ppm: altered breathing 100-300 ppm: pulmonary edema 500-700 ppm: collapse in 5 min, death 30-60 min 1000 ppm: nearly instant death “Heavier than air”
Methane (CH4) – In foaming manure Simple asphyxiant: every 4% increase in methane, 1%
decrease of oxygen Flammable at 5 to 15% (50,000 to 150,000 ppm) Foam: 50-70% Methane (too high to be flammable) When foam breaks: concentration dilutes and becomes
explosive “Lighter than air”
Fact Sheets:
H2S Fatalities (2015)
“Quick” attempt to retrieve equipment from pit resulted in two father-son fatalities in summer 2015
Iowa FACE report 2005 IA 024/025
Preventing Manure Gas Fatalities
Educate/warn: post signs Prevent accidental entries Don’t enter during / just after agitation Ventilate spaces prior to entry Enter only with adequate equipment
Retrieval system (harness, mechanical lift) Standby-by person SCBA Monitor With
Alarm
Foaming Manure Methane (CH4) is trapped in the foam but is
released when foam breaks Sources of breaking foam:
Dropped feed Manure agitation Pressure washing
Methane dilutes to flammable concentrations Sources of combustion:
Electric motors (e.g., pressure washers, feed systems) Pilot lights Welding/cutting Faulty/damaged wiring Smoking
Critical to eliminate combustion sources during activities when foam might break
Preventing Manure Gas Fatalities:Monitors
At-Risk decisions “I don’t have an SCBA, but I only need to go in for a
second.” “I can hold my breath” “I have had the fan on long enough…” “I pumped days ago…”
How can we tell if hazardous gases are at dangerous concentrations? Monitors can provide risk information to producer in real
time Prices are extremely low (single gas H2S ~$100) These units are commonly used in other industries
in high-hazard environments
Preventing Manure Gas Fatalities:How to Select Monitors
Currently:•No information on how long these last when stored in AG environments• Selections based on
purchase cost and warranty• Store in clean environment
•No “industry recommendations” for calibration and sensor (“bump”) check• Bump check before every
use• Calibrate at least monthly
and immediately before planned entries
Preventing Manure Gas Fatalities:Operating Monitors
Prepare to Sample Air for Manure Gases• Ventilate space• Allow sufficient warm-up time• Understand how long it takes your sensor to respond
– May take up to 90 seconds• Obtain tools to measure at a distance:
– 4 feet in front of you in the direction of travel– Mount monitor securely on stick or use probe with extension hose
• Confirm monitor is working:– Bump-test with gas to make sure it alarms– Calibrate per manufacturer’s instructions
• Identify alarm settings: – Be clear what you need to do if monitors alarm
Preventing Manure Gas Fatalities:Operating Monitors
Testing Order and Key Decisions:
1. Oxygen%LEL won’t give reliable numbers if insufficient O2
Need 21% O2
If lower, may have high methane:
Get out!
2. %LEL (flammable methane)
Need <1% LEL
10% LEL or more: Get out!
3. H2S
>10 ppm: Chronic health effects100 ppm: Get out!
The LEL of methane = 5% = 50,000 ppmA reading of “1%LEL” 500 ppm methane
Preventing Manure Gas Fatalities:Operating Monitors
To Test Prior to Entering Manure Pit
Test manure pit while outside of it first
Do not enter!Ventilate space then retest from
outsideSafe?
Test at entry location and every 4 feet (in front, to side, above, below)
No
Yes
Notes:
• Monitors take time to get true concentrations (60 -90 sec).
• We set alarms lower than what can cause death.• Concentrations can go up quickly, so react to low
concentrations as indication of inadequate ventilation.
Preventing Manure Gas Fatalities:Operating Monitors
To Test for Methane Gas in Barn
Washing Barn
1. Prohibit entry2. Prepare ventilation equipment and
monitor3. Implement shut-down for electricity and
gas4.Put monitor on worker during
activity:EVACUATE if %LEL Changes from 0%
5. If evacuate– Continue ventilating room– Return with a monitor, testing in 4 foot
increments, including ceiling level; back out if concentrations still high
– Return to task only when %LEL = 06. When work is completed/foam not at
risk of breaking, continue ventilating until confirm no methane
Hot WorkChanges to feed system
1. Prohibit hot work in barn with foaming manure
2. If work must be done, prevent activities breaking foam
3. Follow all procedures to the left
Pumping Manure Pit
1. Prohibit agitation when less than 2 feet between foam and slats
2. Ensure pit fans are operating
3. Follow all procedures to the left
4.If anyone enters barn, O2, H2S and %LEL monitors should be used
5. Continue ventilating barn after pumping back to background: 21% O2, <1 ppm H2S, 0% LEL
Summary Multiple compounds in the barn are associated with long-term adverse
health effects Respirators or improved ventilation, particularly during winter, can reduce
health risks
Acute hazards from manure gases still pose dangers Procedures via ASABE and Extension recommend ventilation duration and
safety protocols Available inexpensive technology can ensure concentrations throughout
the room are safe for activities• Working with monitors to recommend maintenance and lifetime to
recommend specifics• Developing training
Booth 1210 contains specifics Sign-up sheet for those interested in
classes on using monitors
Questions?Example monitors on display at Booth 1210
Fact Sheets: Ventilation Study:
QR code for gpcah web for farmers
Chronic Health Outcomes
AuthorsDeclines in Lung Function
Increased Respiratory Symptoms
Increased Airway Inflammation
Zuskin (1992) – Netherlands (N=59)
Cross-shift (FVC, FEV1, FEF50, FEF25)Lower pre-shift capacity vs controls
Chronic cough, dyspnea, chest tightness, chronic bronchitis (not ♂, N=41)
Cormier (1991) – Quebec (N=102)
Obstruction (FEV1/FVC, MMFR)
Choudat (1994) – France (N=102)
Lower but insignificant difference (MEF, FEF50, FEF25)
Cough (morning, diurnal, workplace), Work-related sneezing
Pedersen (1996) – Denmark (N=27)
Normal FEV1 More bronchial reactivity: (via bronchoscopy and BAL --increased lymphocytes, neutrophils, increased macrophage activity)
Larsson (1994) – Sweden (N=14, non-farmers)
BAL changes 1 day post exposure
Chronic Health Outcomes
AuthorsDeclines in Lung Function
Increased Respiratory Symptoms
Increased Airway Inflammation
Iverson (1990) – Denmark (N=124 pig, 57 dairy)
No difference in dairy vs pig farmer: FEV1 decrease 12 mL/year of farming
More wheezing, shortness of breath, dry cough compared to dairy farmer
Age, years in pig farming, and smoking all associated with bronchial hyperreactivity (PC20 histamine values)
Iversen (2000) – Denmark (7-yr follow up, N=135)
FEV1 declined more with pig farmer: 53 mL/yr pig (significant) vs 36 mL/yr dairy (not significant)No difference in FVC
Same as previous Small decrease in bronchial hyperreactivity between pig and dairy, only once correcting with FEV1
Vogelzang (2000) – Netherlands (N=171)
Mean FEV1: 73 mL/yr, FVC 55 mL/yr
n/a Increased bronchial responsiveness (associated with NH3, automated dry feeding, wood shavings as bedding)
Studies Relating Exposures to Outcomes
Contaminant Mean Conc.Recommendation To Prevent:
“Total” dust (A) 4.3 mg/m3
(P) 6.8 mg/m3(A) 2.4 mg/m3
(P) 3.8 mg/m3 Chronic cough & phlegm
Respirable dust (A) 0.33 mg/m3
(P) 0.34 mg/m3(A) 0.23 mg/m3
(P) 0.28 mg/m3 Chronic cough & phlegm;
frequent chest colds; febrile episodes
Endotoxin - total (A) 0.18 ug/m3
(P) 0.24 ug/m3(A) 0.08 mg/m3
(P) 0.09 mg/m3 FEV1
Endotoxin - respirable
(A) 0.17 ug/m3
(P) 0.23 ug/m3 n/a n/a
Ammonia 9 ppm 7 ppm FEV50, FEF50
Carbon dioxide 1740 ppm 1540 ppm FEV50, FEF50
Hydrogen sulfide n/d - -Carbon monoxide n/d -
Donham et al., 1989 (Sweden, N=57)
(A) Indicates area sample, (P) indicates personal sample
Studies Relating Exposures to Outcomes
Contaminant Mean Conc. Recommendation To prevent:“Total” dust 4.53 mg/m3 1.3* – 2.8 mg/m3 <10% decrease in
FEV1 (>2 hr /day, 6 yr)
Respirable dust 0.23 mg/m3 - -Endotoxin – “total” 202.35 EU/m3 - -Endotoxin - respirable 16.59 EU/m3 - -Ammonia 5.64 ppm 7.5 ppm 3% decline in FEV1
Carbon dioxideHydrogen sulfideCarbon monoxide
Donham et al., 1995 (Iowa, N=201)
Not reported
*smokers had more response and effects not seen below 1.3 mg/m3
Studies Relating Exposures to Outcomes
Contaminant Mean Conc.Recommended Exposure Limit Association?
“Inhalable” dust 2.63 mg/m3 2.6 mg/m3 YesEntotoxin 105 ng/m3 - NoAmmonia 1.6 mg/m3
(2.13 ppm)5.4 mg/m3 (7.2 ppm) Limited
Vogelzang et al. 2000: Examined bronchial hyperresponsiveness