MONTPELIER, Vt. — Vermont regulators are investigating whether Vermont Gas Systems failed to bury its new gas pipeline from Colchester to Middlebury deep enough in New Haven.

The Vermont Public Utility Commission said Friday that Vermont Gas notified the panel last month that it buried the pipeline less than 4 feet in 18 spots in the town.

The commission says it’s opened an investigation into whether the utility violated its 2013 permit. The investigation will determine if remedial action or a penalty is appropriate.

The panel says it will also require Vermont Gas to submit evidence by Aug. 11 to certify that the rest of the 41-mile pipeline has been buried at the required depth.