Prevent exposure to gases when emptying stored manure

By Carrie Webster

As the weather changes from warm summer days to cooler fall and even colder winter ones, take time to renew your commitment to safety, especially when emptying manure storage and applying nutrients.
“Never rush this task and always focus on safety,” said Karen Hoare, director of producer learning and development for the Pork Checkoff. “Everybody on the farm should be knowledgeable about naturally occurring gases in stored manure.”

These include hydrogen sulfide, methane, carbon monoxide and ammonia.

“Protecting the health of livestock and farm workers is the No. 1 priority,” Hoare said. “That means being able to identify gases released while raising pigs and the possible associated risks for each (see below),”

Simple precautions can prevent exposure to the gases and protect the health of both people and pigs..

“During agitation and pumping, clearly tag all doors and note that the barn is unsafe for entry,” Hoare said. “Don’t allow anybody to enter a barn or manure storage structure when liquid manure is being agitated or pumped or until properly ventilated afterwards. If you must enter a manure storage area, proper equipment and training is needed.”

A supplied-air respirator, either an air-line respirator or self-contained breathing apparatus, that fits properly is appropriate to use along with a standby person and a retrieval system.

“Consider using either single or multi-gas monitors with alarms,” Hoare said. “Properly calibrated monitors can provide real-time information and warnings about gas concentrations.”

Be Ready to Act
“Do not enter a suspected toxic area if someone is unconscious, Hoare said. “Contact emergency medical services according to your farm’s Emergency Action Plan. The bottom line is to be proactive about safety by being prepared.”

You’ll find more safety tips and resources from the Pork Checkoff at

Key Gases Released While Raising Pigs:

Hydrogen sulfide, released during decomposition and agitation of manure, is a flammable, poisonous gas that smells like rotten eggs, but only at very low levels. Higher levels deaden your sense of smell quickly and severely irritate your eyes, throat and lungs. Even low concentrations can cause immediate loss of consciousness and death.

Methane is a colorless, odorless, usually nontoxic gas. However, it is flammable and poses an explosion hazard. Watch for pit foam and use caution when ventilation is reduced. Methane is trapped in pit foam but is released and combustible when pit foam breaks during agitation, pressure washing, etc. Remove sources of combustion if pit foam is present when completing these activities. Do not agitate if pit foam is observed less than two feet below the slat level.

Carbon monoxide is released from unvented heaters and gas-powered pressure washers. The colorless, odorless and very toxic gas can cause death at high concentrations. Gas-powered pressure washers should be used in well-ventilated areas.

Ammonia, released during decomposition and manure agitation, is a pungent, colorless, noxious gas easily detected even in small concentrations. At low levels, it can irritate your eyes, throat and lungs. Long-term exposure may make you more susceptible to respiratory diseases.