The University of Minnesota is reminding pork producers, commercial manure pumpers and others to be alert to the dangers that can occur during pit pumping if there is a layer of foam on the surface of barn manure pits. This warning, according to a report posted by National Hog Farmer magazine, comes after a person was seriously injured in a manure-pumping incident in central Iowa. Manure pit foam contains numerous gases that are hazardous to people and animals. Methane in particular can cause barn explosions and/or flash fires.

"If a 6-in.-thick or greater layer of foam is present and it is disturbed during normal pit agitation and pumping, a sudden release of dissolved gases will occur," says Larry Jacobson, an agricultural engineer with University of Minnesota Extension. Without adequate barn ventilation, this can result in methane concentrations reaching the lower explosive level of 5% or 50,000 part per million (ppm). "An explosion is then likely if an ignition source is present from a pilot light, electric spark from a motor or cigarette," he says.

To guard against pumping accidents, agricultural engineers, animal scientists and pork industry consultants have developed a series of recommendations to help producers address this serious safety concern:

  • Provide continuous ventilation to prevent gas build-up. Increase ventilation during agitation to quickly dissipate released gases.
  • Turn off heater pilot light and other non-ventilation electrical systems, such as the feeding system), that might produce an ignition spark.
  • When pumping pits that are close to being full, pump without agitation until manure is about 2 ft. below the slats.

    National Hog Farmer provides more safety tips to follow when pumping foaming manure pits at