Pig farmer Leon Sheets knows that pit foaming is a dangerous phenomenon. He’s got the scars to prove it.

Sheets, a Chickasaw County Farm Bureau member in Ionia, starting disinfecting an 8-foot-by-40-foot area of a finishing barn on Sept. 14, 2014.

The work area had slatted floors and was situated between four rooms in the building. The ventilation was on low. The room has no primary ventilation since it’s in between rooms. There was a little bit of foam visible in the pits, but it hadn’t reached the slats, Sheets said.

"Somewhere in the process of getting the floor wet, I must have moved some foam and broke some bubbles," Sheets said. "All the sudden there was a ‘wooooom.’ A big ball ...