HEBRON — State environmental officials say most of the 1,900 gallons of heating oil that spilled at a Hebron school last month leached into nearby wetlands.

The Maine Department of Environmental Protection says the oil does not pose a threat to nearby Bog Brook, which flows downstream into Minot and Mechanic Falls.

The spill at Hebron Station School occurred Dec. 24 when the gauge on the school’s oil tank malfunctioned, showing the tank was empty when it was not. When the delivery driver tried to fill it, the oil spilled.

About 135 students were relocated to another school for about three weeks, but have since returned.

The Sun Journal reports that air-quality tests from the gymnasium are expected to be released Friday.

No contamination has been found in the school’s well.