Farmers are at increased risk for inhalation injury from organic dusts and toxic gases. Confined space accidents are relatively common on farms with potentially fatal exposures to carbon monoxide, nitrogen dioxide, and manure gases including hydrogen sulfide and methane. See "Agricultural Operations" at osha.gov. In swine concentrated animal feeding operation (CAFO) rooms during winter months, mean concentrations of ammonia and hydrogen sulfide approach exposure limits. [PMID 23548103] See "Farming (Pesticides)" and "Farming (Feed Additives)."