PARIS — Engineers told district officials Wednesday that a 11,400-gallon oil tank at the elementary school does not pose an immediate risk and can continue being used.

Following an interior and exterior inspection, Gary Perry of Hermon-based Sullivan & Merritt told officials that the tank has interior surface corrosion, but no deep scour marks or pitting.

According to Perry, the corrosion was caused by water, which likely migrated into the tank through condensation or back-flow from an intake pipe. It did not pose an immediate threat to its integrity, he said.

“There’s still two-thirds remaining on the tank’s life-cycle,” Perry said.

The tank’s legs, also damaged by corrosion caused by highly destructive “blow back” boiler water that coursed from a nearby room above the oil tank, were adequate to support it.

As a future course of action, he recommended lifting it at least six inches above the floor onto concrete pillars.

The tank’s condition has been the source of controversy in recent weeks after Paris selectmen sent a letter to SAD 17 Superintendent Rick Colpitts last month, requesting that its volume be reduced.

Paris officials expressed concern that the collapse of or spill from the tank could pose a threat to town’s drinking water supply.

Their move followed in the wake of a 1,500-gallon oil spill at Hebron Station School in December, where oil pooled in a concrete tank room, and eventually seeped below the school and out into neighboring wetlands.

After the spill, Colpitts requested the Maine Department of Environmental Protection conduct a survey of the district’s facilities.

In March, the Maine DEP issued a report outlining oil storage and handling concerns at three schools and the bus depot.

Among the findings in that report, state officials highlighted the “severe” corrosion on the support legs of the tank at the Paris Elementary School.

The tank, which is the school’s primary heating source, rests nearly three-quarters of inch above a concrete floor in an adjacent, self-contained room beneath the school.

The limited gap between floor and tank blocked complete access to engineers, and prior to inspection, Clean Harbors pumped out oil so engineers could enter and take measurements.

Strapped into a harness, Perry climbed down a portable ladder inside the tank, using a handheld ultrasound gauge to measure the thickness of the walls.

David McCaskill, a senior environmental engineer with the Maine DEP, said it was a “mystery” why the tank was never built with a six-inch clearance.

Because groundwater has risen into the basement room in the past, McCaskill recommended material be placed in gaps between the room’s walls and floor to help minimize future corrosion.

Schools have been closed this week as students are on vacation, and Perry agreed the tank could be refilled in time to heat the school for Monday’s classes.

Colpitts, who was on-site Wednesday but left before the inspection was completed, said the engineer’s recommendation will determine whether or not it removes the tank.

School officials have been looking into the feasibility of wood pellet boilers, which were installed over the winter at Guy E. Rowe and Oxford Elementary schools, Colpitts said.

“There are lots of other fueling options,” he said.