Manure Pit Hazards

Farm Safety & Health Digest Vol. 3, No. 4, p. 3

Slide 7

Hydrogen sulfide is the most dangerous gas found in enclosed livestock operations. It is responsible for most manure-related deaths of animals and people.

Within seconds of exposure, hydrogen sulfide can cause unconsciousness, which can be fatal. Concentrations as low as 1,000 ppm can result in death. The maximum allowable concentration is 10 ppm.

Hydrogen sulfide is heavier than air, so it will accumulate in underground pits or other low-lying, unventilated areas. Although its rotten egg odor can be detected at levels of less than 1 ppm, the gas will paralyze the sense of smell at higher levels.

Solution: Whenever you work in manure storage facilities, always assume hydrogen sulfide is present. Follow these safety precautions to minimize the dangers of hydrogen sulfide:
    Provide extra ventilation during agitation.
  • Never enter a pit without precautions.
  • If you suspect high hydrogen sulfide levels for any reason, leave the building immediately.
  • (Source: ISU Extension publication #: Pm-1518k )

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