CONCORD TWP — A foul odor caused by an unknown substance from an abandoned homemade trailer fitted with a plastic container prompted a response Wednesday morning from a fire department and Butler County's Hazardous Materials Team.

The mystery at the Rolling Ridge Farms on Bryan Road grew when the farm manager had to be taken to the hospital after becoming ill from inhaling the unidentified substance.

A little later, state police showed up to join in the investigation.

But nearly two hours after the initial call at 9:20 a.m., the emergency crews determined there was no safety concern.

The substance, first believed to be some type of chemical, possibly weed killer, turned out to be diesel fuel.

That fuel, as much as 180 gallons, was stolen from a tank inside the farm, Dave McElheny, who manages the farm, said this morning. He suspected the homemade contraption that he found Wednesday was intended to haul away the fuel.

But the shoddily crafted devise apparently broke and the thief abandoned it just outside the gate leading to the farm's entrance, about one-half mile west of Route 38.

The investigating trooper did not immediately file a report, and police this morning had no other information about the case.

Chief Nick Grove of the North Washington Volunteer Fire Department said firefighters were called to the farm after McElheny's discovery and his sudden illness.

“I got a headache real bad,” McElheny said

A Petrolia Ambulance crew was called and took him to Butler Memorial Hospital, where he was given oxygen He was released about 90 minutes later.

Back at the sprawling Rolling Ridge Farms, owned by Harold Snyder, emergency crews were trying to make sense of the substance that had leaked from the plastic container on the abandoned trailer.

“It may be weed killer or diesel fuel,” Grove speculated. He called in the hazmat team for precautionary reasons.

“It smells like some sort of pesticide or herbicide,” Scott Hoffman, the county's hazardous materials specialist, said shortly after getting there.

While the substance had yet to be identified, Hoffman declared “everything clear”about 11 a.m.

He collected a sample of the substance before leaving.

An official for the state Department of Environmental Protection showed up later in the afternoon and also took a sample.

But McElheny said authorities eventually determined the substance was fuel, stolen from the farm.

He suspected what had left him temporarily ill was the military grade fuel stabilizer the farm adds to the diesel fuel.

“It's added to extend the life of the fuel,” he said.