Sanitary workers cleaning septic tanks trapped by methane gas is commonplace in developing countries like India.
It is now catching up in the West too. Fiver persons fell victims to the deadly methane emanating from a manure pit in a dairy farm in Shenandoah Valley, Virginia, US Monday evening.
Scott Showalter, 34, a Mennonite farmer who climbed into the pit to unclog a pipe was the first to be killed by methane. His wife, two young daughters and a farmhand followed in his trail.
Farmers typically take pains to ventilate manure pits where methane often gathers. A family member questioned whether cattle feed could have trickled into the pit and accelerated the formation of the gas.
"You cannot smell it, you cannot see it, but it's an instant kill," explained Dan Brubaker, a family friend who oversaw the construction of the pit decades earlier.
About once a week, waste is pumped from the roughly 9-foot-deep pit into a larger pond. When something clogged the drain, Showalter shimmied through the 4-foot opening into the enclosure, which is similar to an underground tank. He would have climbed down a ladder into about 18 inches of manure.
"It was probably something he had done a hundred times," Sheriff Donald Farley said. "There was gas in there and he immediately succumbed."
Believing Showalter had suffered a heart attack, police said, a farmhand followed him moments later and also passed out.