BISMARCK, N.D. (AP) – A North Dakota regulator on Wednesday criticized the company developing the Dakota Access pipeline for waiting 10 days before reporting that American Indian artifacts were found last month along the route.

In an Oct. 27 letter, a subsidiary of Texas-based Energy Transfer Partners notified the Public Service Commission that stone cairns and other artifacts had been found in mid-October. Consultants determined there was a “low likelihood” for buried artifacts and recommended avoiding the site.

Julie Fedorchak, the PSC chairwoman, said she was disappointed regulators weren’t notified earlier. The matter was to be discussed at a PSC meeting Wednesday.

The potential for damage to American Indian sites and artifacts has been a flashpoint in a months-long protest over the pipeline, which is intended to carry crude from western North Dakota almost 1,200 miles to a shipping point in Patoka, Illinois. The Standing Rock Sioux, whose reservation lies near the pipeline route, have led a protest over that issue and the pipeline’s potential hazard to drinking water.

Tribal officials said in September they had identified cultural artifacts on private land along the route. North Dakota’s chief archaeologist, Paul Picha, later inspected the area and said no sign of artifacts or human remains had been found.

Picha said he was notified of the most recent discovery in a timely manner but didn’t report it to the commission because he thought the pipeline company would. He said the site was properly handled.

The 1,172-mile pipeline is largely complete outside of North Dakota. The federal government in September ordered a temporary halt to construction on corps land around and underneath Lake Oahe, a Missouri River reservoir in the Dakotas. The corps is reviewing its permitting of the project but has given no timetable for a decision.