A confined-space hazard often claims multiple lives before anyone realizes there is danger in manure gas. Manure pits can be oxygen-deficient, toxic and explosive. There are four gases in manure pits that are of primary concern.

Carbon dioxide
Carbon dioxide is an odorless, tasteless gas that is heavier than air. It displaces the oxygen supply in the bloodstream, which can cause unconsciousness and death.

Hydrogen sulfide
Hydrogen sulfide is a highly toxic gas that is heavier than air. It can cause dizziness, unconsciousness and death. At low concentrations it may smell like rotten eggs, but at higher concentrations it deadens the sense of smell so no odor can be detected.

Methane
Methane is a gas that is lighter than air. The primary hazard of methane gas is that it can create an explosive atmosphere. This gas also displaces oxygen.

Ammonia
Ammonia is a gas that is also lighter than air. It has a pungent smell and can irritate the eyes and respiratory tract. Ammonia also displaces oxygen in the bloodstream.

Safety practices
–Obtain and use monitoring equipment to determine the level of gases present in the manure storage area.
–Never enter a manure pit alone.
–A self-contained breathing apparatus must be worn when entering a manure storage area, and the person wearing it should be trained in its use. A safety harness should also be worn and personnel should be available outside the storage area to monitor the entrant’s progress.
–Label the manure pit and manure storage areas to warn of the gas hazards.

Inspection
–Do fences or metal-grill covers restrict pit access?
–Are manure gas warning labels near the pit?  ANM

—From the National Safety Council, Agricultural Division Copywrite 2006 Progressive Dairy Publishing. All Rights Reserved.