CANTON, Ohio (AP/WCMH) — Ohio’s environmental watchdog agency has increased the proposed penalty for the builder of a high-pressure natural gas pipeline after tests found diesel fuel in drilling mud spilled in a wetland.

The Canton Repository reports the Ohio Environmental Protection Agency said Thursday it’s proposing to raise the penalty against Rover pipeline builder Energy Transfer from $430,000 to $914,000. The agency has ordered the company to monitor groundwater near the spill area and a quarry where mud was dumped.

The newspaper reports the quarry is near a well that supplies drinking water to 40,000 Stark County customers. The Federal Energy Regulatory Commission said Thursday it wants records related to mud disposal preserved for the $4.2 billion project. An Energy Transfer spokeswoman says the company is cooperating with both agencies.

In April, about 2 million gallons of a non-toxic, clay-based lubricant called bentonite spilled as Rover Pipeline workers drilled beneath the Tuscarawas River near Navarre in Stark County. The spill covered 500,000 square feet and was caused by pressure during drilling. The next day, an additional 50,000 of bentonite spilled in Richland County after a pump failure.

Energy Transfer is the same company behind the controversial Dakota Access Pipeline, which got the green light to continue construction from the Trump administration earlier this year. Last month, it was reported that the Dakota Access Pipeline had sprung two more leaks, leading opponents of the pipeline to call for additional environmental reviews.

___The Associated Press contributed to this report.