Gasoline leakage went unnoticed; Mr. Mike's gets site-cleanup order.

Byline: Mary Jo Hill

LEOMINSTER - As much as 9,500 gallons of gasoline may have leaked from a Mr. Mike's Mobil gas station near Interstate 190, and while the petroleum product has been found in the ground, the only nearby drinking water well hasn't been contaminated, according to a news release from the state fire marshal's office.

The state Department of Environmental Protection has required the company to install extraction pumps to remove gasoline and gasoline vapors from the ground, according to the release.

The drinking water well continues to be monitored closely, the release said.

A longer-term remediation plan must be submitted to the DEP by May 11.

The busy gas station and convenience store is at 280 New Lancaster Road (Route 117).

The leaking fuel was discovered March 12 when employees at Mr. Mike's saw gas coming from underneath the fuel dispenser and shut off the pump. Subsequent testing showed a failure of the line between the tank and the mid-grade fuel dispenser, the release said.

Early on, the DEP said about 1,000 gallons of gas couldn't be accounted for at the station and it was possible that the missing gas was the result of a paper error.

But yesterday, Jennifer Mieth, a spokeswoman for the fire marshal, said the missing gas was the result of a leak, and the amount lost was as much as 9,500 gallons.

Pressure testing of the piping to other tanks at the station showed they were secure, the release said.

"When the site of the existing piping is excavated, code compliance officers should get a better understanding of what caused the failure," the release said.

Code compliance officers from the fire marshal's office and members of the Leominster Fire Prevention Bureau are working to determine the cause of the failure. The DEP is monitoring the situation.

Leominster Fire Chief Ronald Pierce said there is no fire or explosion hazard at the station.

Excavation should start this week or early next week and probably will take a few days, Ms. Mieth said.

Peterborough Oil Co. in Leominster, which owns the station, has been excavating to install new piping leading to all pump dispensers, said Tim Petersen, operations manager for Peterborough.

"We're replacing all the supply lines to the pumps out front," Mr. Petersen said.

The new piping terminates in a sump, which will be monitored for leakage, and the existing dispenser piping on the pad will be connected to this, according to the fire marshal's office.

Mr. Petersen said there appears to have been a massive leak two or three days before it was discovered. The station has four 20,000-gallon tanks, Mr. Petersen said.

But there had been warning signs in the daily inventory records for months of a possible leak, Ms. Mieth said.

"Failure to notify authorities of continued unexplained product loss is a violation of the State Fire Code," the fire marshal's release said.

The company was issued a notice of violation that carries a penalty of about $100 for the failure to maintain proper inventory records and to conduct a monthly reconciliation.

"The true cost to them is going to be the cost of remediation and replacement," Ms. Mieth said.

The cost will be borne by the gas station owner, said Joseph M. Ferson, a DEP spokesman. The more elaborate the remediation, the more expensive it will be, he said.

Owners of underground storage tanks must maintain daily inventory records that show how much gasoline is in each tank at the start and end of each day and the amount of product dispensed by and delivered to each tank each day, the release said. It took the company about four weeks to reconcile its inventory records at the request of fire officials, the release said.

Mr. Petersen said the company is still investigating its inventory records to determine if they're 100 percent correct. It hasn't received any legal documents about the violation from the fire marshal, he said.