ORLAND – Two state agencies are investigating the dumping of several thousand gallons of wastewater from a collection tank at the Maine Department of Transportation garage onto the ground behind that facility.

Officials from the DOT and the Department of Environmental Protection on Wednesday were at the garage, located off Gilpin Road, to inspect the site and to gather samples from the collection tank.

The incident happened a week ago when crews opened the pump on the 3,000-gallon wastewater collection tank and sent as much as 2,500 gallons of the wastewater onto the ground.

“If they were pumping, it’s because an alarm went off telling them the tank was nearly full,” Brian Pickard, a highway maintenance engineer with the DOT, said Wednesday. “My guess is that they pumped 2,000 to 2,500 gallons unless they stopped when they realized something other than clear water was coming out.”

The tank was supposed to contain just meltwater off the DOT trucks. That would be the same components – snow, sand and grit – that would have melted onto the ground if the trucks had been left outside during a warm, sunny day, according to Tammy Gould, a DEP environmental specialist who coordinates the monitoring of floor drains in garages around the state.

The dumped wastewater, however, left a darker than normal patch on the ground, fueling suspicions that other materials, which could include oil, antifreeze, gasoline or other fluids found in any garage operation, may have gotten into that tank.

DEP investigators took samples from the tank during an initial inspection last Thursday, and Gould said they took additional samples Wednesday. The samples have been sent to the DEP lab, but no results have come back yet, she said.

“It would be premature to speculate what might be there,” said Dwight Doughty, a hydrogeologist with the DOT’s Office of Environmental Services.

Many garages around the state have floor drains, Gould said, but if they are not connected to a municipal sewer system, a holding tank generally is required in order to prevent toxic materials, such as oil and antifreeze, from getting into the environment. The collected fluids are supposed to be pumped and hauled by a hazardous-materials hauler and disposed of at a municipal treatment plant.

Under rules the DEP has provided to the DOT, however, there are exceptions, Pickard said.

If the floor drain is not attached to a bay where mechanics are working, and if the materials are tested, they can be dumped onto the ground as long as it is not in a sensitive area such as a wetland, Pickard said. DOT crews use that option, he said, because it is expensive to haul those materials from the site.

The crew in Orland had tested the tank contents last Thursday before they pumped, Pickard said.

“It’s possible that they did everything they were supposed to,” he said. “If it [the tank] wasn’t attached to a mechanic’s bay, then they did everything according to Hoyle.”

It is also possible that a hydraulic leak occurred during the pumping, which would account for the foreign material in the water, Pickard said.

There also may be a problem with the floor drains and tank themselves.

Pickard noted that there is only one collection tank at the Orland facility.

If there was a discharge of hazardous materials, it should not have happened, he said.

“We will still take corrective action to make sure that this does not happen elsewhere,” he said.

There is also the possibility that the materials were dumped onto private property.

William Clark, who lives next to the DOT garage, is involved in a property line dispute with the department. Clark, who reported water release to DEP, claims that the materials were pumped onto property he owns and onto his son’s land as well.

Gould said she was unsure where the property lines were and has not determined whether the materials were pumped onto private property. That would not affect the investigation, she said.

At this point, the concern is more procedural than environmental, Gould said.

“We want to make sure that this does not happen again, just as they want to make sure it doesn’t happen again,” she said.

Because of the season, the environmental danger from whatever was dumped onto the ground is minimal, she said.

“The materials are probably suspended in the snow or laying on frozen ground,” she said. “It’s unlikely that it’s running anywhere.”

The DEP’s enforcement unit in Bangor will work with the DOT to clean up the materials, she said.

Because the incident could result in disciplinary action, the DOT is conducting the investigation under procedures outlined in the collective bargaining contract with the Maine State Employees Association.

A three-member panel from the DOT will conduct that investigation. The DEP will submit questions to that panel.

That investigation probably will last into next week, Doughty said.