The illegal sale of sodium cyanide to beekeepers across the country - uncovered when three barrels of the deadly chemical tumbled off a truck - appears be limited to a single distributor in North Dakota, the Environmental Protection Agency says.

"We haven't found any evidence other than in North Dakota of widespread use," said Tim Osag, an EPA enforcement coordinator in Denver. "I'm not saying that it's not possible that people are getting their hands on it from another source - but we've been unable to identify that."

The three barrels of sodium cyanide fell off the back of John Roeder's truck in northeastern North Dakota last September.

Two of the barrels were immediately found by farmers and turned in to officials. The third barrel was not found until October, after a weeklong air and ground search that included the FBI and the chemical's maker, Dupont Co.

The incident sparked a federal probe into how prevalent the illegal use of the chemical is among beekeepers. Some have found it to be the most effective poison to control such pests as wax moths in their honeybee hives.

Sodium cyanide, which turns into a lethal gas when it gets wet, largely is used in the commercial chrome plating, mining and pharmaceutical businesses. It is not registered as a pesticide.

The Environmental Protection Agency's regional offices throughout the United States conducted the beekeeper probe, which concluded this month.

The state earlier announced fines against EnviroKem, a Washburn-based company, and 10 beekeepers for illegally using sodium cyanide as a pesticide. The fines totaled about $190,000.

Agriculture Commissioner Roger Johnson said six beekeepers had settled up as of late last week, and the other cases, including the case of John Roeder and his brother Paul, and EnviroKem, are pending.

The largest fine of $54,000 was levied against EnviroKem and its owner, Randy Salli. The company, which has a warehouse in Minot, is accused of illegally handling more than four dozen containers of sodium cyanide from 2003 to 2004.

Johnson said state officials know that drums sold by EnviroKem went to Florida, Nebraska, Minnesota and California. He said all 54 containers handled by the company in the past two years have been destroyed.

Randy Salli, the owner of EnviroKem, did not return repeated telephone calls from the Associated Press.

A worker at the company's Minot facility, who would identify himself only as "Mike," said Salli was out of the state on vacation until November.

He said no beekeepers had inquired about purchasing the chemical since the federal investigation began.

"Beekeepers love it," he said of sodium cyanide. "But word has got out. Beekeepers are like brothers."

North Dakota and California are the nation's top honey-producing states. North Dakota has 180 licensed beekeepers.

Officials in California fined two brothers who run a honey farm in Redlands $250 each for illegally using sodium cyanide to fumigate their hives, said Veda Federighi, a spokeswoman for the California Department of Pesticide Regulation.

Federighi said Steve and Brian Bouye admitted to using six 110-pound drums on their hives. The brothers said they bought the chemical from EnviroKem's warehouse in Minot.

"It was all used up by the time we talked to them," Federighi said. "They threw the drums out in the trash. They didn't hide anything. They were very open about it."

Paul Roeder, who runs an apiary operation near Hebron with his brother, said it was well known among beekeepers that the chemical could be purchased from EnviroKem, which normally sells janitorial supplies and soap to commercial car washes.

Paul and John Roeder have been fined $34,000 for using and transporting the chemical. The brothers have not settled with the state.

"We didn't know if it was legal or not," Paul Roeder said. "We assumed that since we could get it, that it was legal. This has been a big wake-up call."