BUTLER TWP —- Four construction workers were treated Wednesday for possible carbon monoxide poisoning.

Brian Mazzanti, chief of the South Butler Volunteer Fire Department, said the workers, all adults, had been working on the foundation of an unfinished home on Clark Avenue.

Mazzanti said the men had been using a gasoline-powered machine to pump and maneuver concrete for two to three hours before they became ill.

The owner of the company for whom the men worked called authorities between 9 and 10 a.m. to report the problem, Mazzanti said.

The men were conscious, but ill, Mazzanti said.

Butler Ambulance Service took the men to Butler Memorial Hospital for treatment.

One of the men appeared more seriously affected than the others, Mazzanti said.

The men's names were not released and their conditions were not available.