HOULTON – It’s almost an annual occurrence: fumes or fuel in the sewer or storm-drain system.

The Houlton Fire Department was called at about 10 a.m. Thursday by employees at Carquest on Bangor Street reporting that they could smell gasoline in the building.

A pumper was dispatched, and, while firefighters could smell gasoline, they could find no source for the fumes.

While they were at Carquest, firefighters learned that fumes also had been smelled at the Daigle Oil Co. filling station and carwash across the street.

As was the case at Carquest, fumes were present, but no source could be found.

The Fire Department was called back to the oil company at 5:30 a.m. Friday to check again on a report of gasoline fumes, but the result was the same as the day before.

“We were unable to discover where the problems originated from, and we couldn’t get any sample of petroleum product at all,” Houlton Fire Chief Milton Cone said Friday.

He added that sensor readings taken at both sites, as well as in the sewer line in the area, did not indicate that the fumes were at an explosive level.

“As a precautionary measure, we opened up three of the sewer [manhole] caps in what we felt was the affected area,” he said.

The manholes were covered with grates and left open all night Thursday.

Businesses in the area also were advised to turn off their furnaces for a short time until the extent of the problem could be determined.

It was reported that people working in the area have smelled fumes on and off for several weeks. The fumes most often were smelled after a building had been closed up overnight. The smell was detected when employees came to work in the morning.

For most of Thursday and part of Friday, Houlton Water Co. employees tried to find the source of gasoline fumes in the area around the intersection of Bangor and Sugarloaf streets.

John Clark, general manager for the water company, said Friday that samples of the water in the sewer line were taken and absorbent pads were placed in the line in an effort to find any fuel that might be in the system. Both types of examinations had negative results, he said.

“We have no evidence at the [sewage treatment] plant, and this has been going on for 11/2 days,” Clark added.

Fumes or fuel in either the sewer line or municipal storm-drain system have been an on-and-off occurrence in Houlton over the past dozen years. In 1989, fumes were detected in the sewer line that runs through downtown. Gasoline fumes also were detected in the sewer system in August 1992 and in a storm drain off Main Street in the spring of 1998.

In September 1993, a house on Pleasant Court was damaged after gasoline fumes in the sewer line caused an explosion. Fumes were detected in 20 other homes in the area.

There have been other reports since then of fuel or fumes, but the most dramatic case came in February 1998 when, over a 21/2-week period, an estimated 10,000 gallons of diesel fuel escaped from the Irving Oil Corp. bulk plant on Leonard Street. The fuel entered an old sewer pipe that ran through the plant, prompting a massive cleanup and containment effort.

Irving has since installed state-of-the-art detection and monitoring equipment at the plant and the sewer line has been routed away from the site.

Clark said all companies that have fuel in the affected area this week, including bulk plants and convenience stores, were contacted, and none reported any fuel losses.

Since no fuel was found, Clark said the water company plans to drill holes into the manhole covers to allow the sewer line to vent itself. He said that is safer than leaving the covers off and will allow venting to go on continuously.

The sewer line was rechecked Friday and, “we didn’t smell anything this morning coming from any of our manholes,” Clark said.