A state investigation into the illegal use of sodium cyanide by some North Dakota beekeepers is focusing on at least half a dozen people and includes two growing seasons.

Regulators want to know how widespread the use of the potentially deadly chemical is in the beekeeping industry.

"It's a wonder someone hasn't been killed yet," said Tim Osag, an enforcement coordinator at the Environmental Protection Agency regional office in Denver.

Glenn Brank, a spokesman for the Department of Pesticide Regulation in California, another top honey-producing state, said there is no evidence that sodium cyanide is used there.

"We don't know anything about that, and we don't want to," he said.

The North Dakota Beekeepers Association, which represents about 200 producers, says the use of cyanide is not standard practice in the state. It is not illegal to possess the chemical, which is largely used in the commercial chrome plating and mining businesses, but it is against the law to use it for an unregistered purpose.

"You get mavericks in any industry," said Floyd Jacober, a Mandan beekeeper. "You get people that … don't want to follow the rules. They just want to be hard-nosed, do it their way."

The EPA and other agencies, including the FBI, monitored the Agriculture Department search for a missing 15-gallon drum of sodium cyanide that fell off a truck in northeastern North Dakota. The chemical was being hauled for beekeepers and was discovered missing late last month. The container was found Tuesday night, nestled under cattails in a ditch near Lawton.

"A potential tragedy was avoided," Agriculture Commissioner Roger Johnson said Wednesday.

Sodium cyanide, which turns into a lethal gas when it gets wet, is not registered for use as a pesticide. It is sometimes used to fumigate hives at the end of the bee season.