VERNAL — State environmental officials are investigating two incidents in which pollution was found around rivers in eastern Utah.

A leak from a natural gas well reserve pit one mile south of the White River was reported to the Bureau of Land Management on Thursday, BLM officials said in a news release Friday. The BLM was told of the leak by Enduring Resources, a Colorado-based energy exploration company.

Although the lined reserve pit is located on property managed by the Utah School and Institutional Trust Lands Administration, it had leaked about 1,200 gallons of drilling fluid across BLM-managed land in Atchee Wash, which is about 40 miles south of Vernal.

The site is part of the company's Rock House Project, which includes plans to develop 55 natural gas wells with roads, pipelines and well pads. The project has drawn criticism from environmentalists and recreation-oriented groups, who had gathered about 33,000 comments by this past December opposing the company's plans. The opposition was organized by the Southern Utah Wilderness Alliance, the Natural Resources Defense Council and The Wilderness Society.

Enduring Resources Vice President Alex B. Campbell said when the leak was discovered this week, crews immediately constructed two berms in an attempt to contain the spill. They then used a vacuum truck to remove the fluid from the berms and empty the reserve pit. The fluid was stopped about one mile away from the White River, Campbell said.

Samples of the drilling fluid have been recovered for testing.

Scott Hacking, a district engineer with the state Department of Environmental Quality, was slated to make an assessment of the reserve pit spill site Friday. He was not available for comment at press time.

Reserve pits are used to store drilling fluids during well operations. The leaking pit is a fresh water/mud system that could contain barite, a component of drilling fluid used to add weight and minimize fluid loss into fractured underground formations.

The White River enters northeastern Utah from Colorado. It empties into the Green River, which was the focus of an investigation by the state Division of Water Quality earlier this week after the agency received reports of foul-smelling foam on the river.

Test results indicate the foamy, smelly substance found floating in the Sand Wash area of the Green River last week isn't harmful, but the testing was not done until eight days after the foaming was first reported. Sand Wash is a popular put-in or launching area for Green River rafting through Desolation Canyon.