HAMILTON (Mercer) — A Mercer County gas station was closed this week as an investigation continued into how water got into the station's gasoline supply.

Nine customers said their cars stopped working on Sunday morning between 9:50 a.m. and 10:15 a.m. after filling up with regular at the Delta station on Route 33 at George Dye Road, according to police Sgt. Brian Schroeder.

After water was found in the gas tanks of the cars, the Mercer County Department of Weights and Measures  shut the station on Monday and state Department of Environmental Protection issued an order stopping deliveries.

Employees told police they believed the water was in a delivery of new gas received on Saturday night.

DEP spokesman Larry Hajna said Tuesday that both agencies continued to investigate how the gas was contaminated.

"We're not clear if it was a delivery issue or had something to do with the weather and a structural issue with the tank," Hajna said.

He said it's an involved process that requires the station's tank to be drained and the lines to the pumps to be flushed.

The station will reopen after Weights and Measures tests a fresh supply in the tanks.

In a separate incident, a Delta gas employee was seen by an officer dumping a clear liquid believed to be water from a shop vac into a storm drain. The worker was told to dispose of the material properly after the officer determined there was no smell to the liquid.

The gas station did not return a request for comment Tuesday.

Contact reporter Dan Alexander at Dan.Alexander@townsquaremedia.com or via Twitter @DanAlexanderNJ