The working conditions in CAFOs are highly dangerous to the employees, and rank among the most hazardous of all occupations.1 Gases and particulate matter found in the air within the factories can cause severe respiratory health effects, including symptoms of pulmonary disease and abnormalities in the lung functions of CAFO workers.
Sinus infections, mucous membrane irritation, bronchitis, asthma, asthma-like syndrome and chronic obstructive pulmonary disease are all conditions experienced by CAFO workers.2 Acute toxicity from high-dose gas exposures (e.g., nitrogen oxides, hydrogen sulfide, ammonia) and interstitial diseases (hypersensitivity pneumonitis, interstitial fibrosis) also are well documented.3 Microbial exposures, especially endotoxin exposure, are related to deleterious respiratory health effects, including short term and persistent declines in lung function.4 Many adverse respiratory effects of farming result from the wide spectrum of respiratory toxicants (eg, organic and inorganic dusts, gases, agrochemicals, biologic agents) as well as the exposure to high concentrations of those toxicants.
Decomposing manure releases various forms of hazardous materials:
- Dust particles and toxins. Small particles—around 50% of CAFO dust particles—pose a significant respiratory hazard because they penetrate deeper into lungs, carrying toxic gases adsorbed onto them.5
- Endotoxins are parts of bacteria remaining toxic long after the organism dies. Even at low concentrations in dust, they can affect white blood cell counts, cause fever and respiratory distress, and worsen asthma. Endotoxins may be a more significant contributor to workers’ problems with chronic cough and bronchitis than dust.6
- Volatile organic compounds (VOCs). Of 331 VOC and gas compounds found in odorous air samples from North Carolina swine facilities, 157 are known airway irritants. Exposure to VOC mixtures can have additive effects, so that sub-irritant levels of individual compounds can cause airway irritation when combined.7
- Ammonia. At moderate to high exposures, ammonia can cause severe cough, and lung inflammation and scarring, edema and death. Ammonia absorbs onto dust particles inhaled deep into lungs, where it can irritate tissue even at low concentrations.8
- Hydrogen sulfide. Over half of swine manure pits may be capable of producing environments poisoned with H2S. H2S is a cyanide-like gas that prevents cells from using oxygen. Acute effects include eye and respiratory irritation at air concentrations of 20 parts per million (ppm), nausea and vomiting at 50 ppm, dizziness at 200 ppm, and loss of consciousness and perhaps death at 500 ppm and above.9
The respiratory problems experienced by CAFO workers include the following:
- Asthma and other respiratory problems. Manure-related air pollutants can inflame tissue around the airways (bronchial tubes), increasing mucus production. Chronic inflammation can permanently scar the lungs. Either mucus or scarring can reduce airway diameter, making it harder to move air in and out of the lungs. One result is wheezing, or the sensation of being short of breath. CAFO workers exposed to these air pollutants report an interrelated group of respiratory symptoms that may occur simultaneously10:
- Occupational asthma. 25% of swine workers have occupational asthma – chest tightness, wheezing, and shortness of breath—typically after six or more years of exposure.11
- “Asthma-like syndrome.” A collection of symptoms—chest tightness, wheezing, cough, and fever—displayed by workers returning after two or more absent days. Documented in 11% of Iowa confinement workers.12
- Sinusitis. Inflamed, swollen sinus passages and eustachian tubes (leading to the middle ear) producing symptoms—headache or tooth pain, head congestion, difficult nasal breathing, and “popping” ear—reported by about 25% of confinement workers.13
- Bronchitis. Airway irritation induced by inflammation. 25% of swine workers report chronic bronchitis, coughing, and phlegm production in three weeks out of a month for two years or more.14
- Among young swine workers, ages 26 to 35, nearly 19% report chronic cough and 24% report chronic phlegm and wheezing; swine workers as a whole had even greater reported chronic cough, phlegm and bronchitis.15
- Organic toxic dust syndrome. A collection of flu-like symptoms—headache, joint and muscle pain, fever, fatigue, weakness, and irritation of the airways and cells lining small lung sacs—reported by one-third of confinement workers.16
Dozens of CAFO workers have been killed as a result of exposure to high concentrations of hydrogen sulfide gas in manure pits.17 Routine, long-term exposure to H2S, even at much lower levels, may lead to permanent declines in brain and nervous system function, and depression and other mood changes.18
In a recent occurrence, four investigators from the state of Maine had to receive medical treatment when they became ill after investigating animal-cruelty allegations at an egg CAFO. They experienced burning in the nose and eyes, coughing, tightness of breath, and sought medical attention for ammonia exposure. It was confirmed that they had experienced an irritation to their lungs merely as a result of being inside of the barns that they were investigating.19
It is possible for multi-drug resistant bacterial pathogens, such as Enterococcus, staphylococci, and streptococci to be inhaled by CAFO workers and result in infections with the drug resistant bacteria. The streptococci are linked to life-threatening infections in immune-compromised individuals.20
Current OSHA standards fail to protect CAFO workers because several hazardous air pollutants are not regulated.21
1 Mitloehner, Frank M. and Marc B. Schenker.
Environmental Exposure and Health Effects From Concentrated Animal Feeding Operations. Epidemiology: 18: 309-311 (May 2007).
Osorio, A.M., Beckman J., Eiser C.R., et al. California Farm Survey of Occupational Injuries and Hazards (Special Issue). J Agric Safety Health. (1):99-108 (1998).
Hendricks, K.J., Adekoya N. Non-Fatal Animal Related Injuries to Youth Occurring on Farms in the United States. Inj Prev. 2001;7:307-311 (1998).
Layde P.M., Nordstrom D.L., Stueland D. et al. Animal-Related Occupational Injuries in Farm Residents. J Agric Safety Health. 1996;2:27-37.
Miller, R.L., Webster J.K., Mariger S.C. Nonfatal Injury Rates of Utah Agricultural Producers. J Agric Safety Health. 2004;10:285-293.
2 Id.
3 Mitloehner, Frank M. and Marc B. Schenker. Environmental Exposure and Health Effects From Concentrated Animal Feeding Operations. Epidemiology: 18: 309-311 (May 2007).
4 Thorne, P.S., Kulhankova K., Yin M. et al. Endotoxin Exposure is a Risk Factor for Asthma: The National Survey of Endotoxin in United States Housing. Am J Respir Crit Care Med. 2005; 172:1371-1377.
5 Donham, K.J. The Concentration of Swine Production: Effects on Swine Health, Productivity, Human Health, and the Environment. Veterinary Clinics of North America: Food Animal Practice 2000, 16(3):559-597.
Schwartz, D.A. et al. Airway Injury in Swine Confinement Workers. Annals of Internal Medicine 1992; 116(8): 630-635.
6 Zejda, J.E. et al. Respiratory Health Status in Swine Producers Relates to Endotoxin Exposure in the Presence of Low Dust Levels. Journal of Occupational Medicine 1994; 36:1:49-56.
7 Shusteman, D. Critical Review: The Health Significance of Environmental Odor Pollution. Archives of Environmental Health 1992; 47(1):76-87.
8 Macher, J.M. (Ed.). Bioaerosols: Assessment and Control. American C onference of Governmental Health Issues, Animal Agriculture, GEIS. Prepared for Minnesota Planning, January 2001. Accessed June 23, 2004 at http://www.eqb.state.mn.us/geis/TWP_HumanHealth.pdf
9 Doss, H.J. et al. Beware of Manure Pit Hazards. National Ag Safety Database 2002 (Accessed June 23, 2004 at http://www.cdc.gov/nasd/docs/d001001-d001100/d0010970d001097.html).
10 Wallinga, David, M.D. Concentrated Animal Feeding Operations: Health Risks to Farmers and Workers. Institute for Agriculture and Trade Policy (Oct. 2004).
11 Donham, K.J. The Concentration of Swine Production: Effects on Swine Health, Productivity, Human Health, and the Environment. Veterinary Clinics of North America: Food Animal Practice 2000, 16(3):559-597.
12 Donham, K.J. Preventing Respiratory Disease in Swine Confinement Workers: Intervention Through Applied Epidemiology, Education, and Consultation. American Journal of Industrial Medicine 1990; 18:241-261.
13 Von Essen, S. and Donham K. Illness and Injury in Animal Confinement Workers. Occupational Medicine: State of the Art Reviews. 1999; 14(2):337-350.
14 Zejda, J.E. et al. Respiratory Health of Swine Producers: Focus on Young Workers. Chest 1993; 103:702-709.
15 Id.
16 Doss, H.J. et al. Beware of Manure Pit Hazards. National Ag Safety Database 2002 (Accessed June 23, 2004 at http://www.cdc.gov/nasd/docs/d001001-d001100/d0010970d001097.html).
17 Wallinga, David, M.D. Concentrated Animal Feeding Operations: Health Risks to Farmers and Workers. Institute for Agriculture and Trade Policy (Oct. 2004).
18 Id.
19 Thistle, Scott. “State Workers Fall Ill After Egg Farm Investigation,” Sun Journal (April 22, 2009). Accessed April 13, 2009 at: http://www.sunjournal.com/story/312210-3/MaineNews.com).
20 Smith, Tara C., et al. Methicilin-Resistant Staphylococcus aureus (MRSA) Strain ST398 is Present in Midwestern U.S. Swine and Swine Workers. PLoS One 4:1:e4258 (January 2009). Accessed at www.plosone.org.
21 Iowa State University and the University of Iowa Study Group. Iowa Concentrated Animal Feeding Operations Air Quality Study: Final Report. Environmental Health Sciences Research Center: University of Iowa, February 2002. (Accessed May 14, 2003 at http://www.public-health.uiowa.edu/ehsrc/CAFOstudy.htm).
