Responders on Saturday were still working to contain a Prudhoe Bay well that shot natural gas and crude oil onto a well pad and may have impacted nearby tundra.

Oilfield operator BP Alaska said in an email that an overflight appeared to show the "unplanned release of hydrocarbons" was limited to the gravel pad around the wellhead north of Deadhorse and plans "a full assessment of the impacted area" in the future.

"The well is currently venting gas, which caused a spray of crude to impact the well pad," according to a report issued Saturday by the DEC. State spill responders were organizing a team to investigate the release.

As of Saturday afternoon, an estimate of the spray volume released was not available, according to the Alaska Department of Environmental Conservation.

Employees with BP discovered the "uncontrolled gas release" from the top of a well house at 7:30 a.m. Friday, DEC said.

Crude oil spraying from the top of the well house was confirmed at 8:15 a.m., the agency said. BP reported the spill 30 minutes later.

"No people were in the vicinity of the well at the time of the release and there are no injuries," said Brett Clanton, with BP U.S. Media Affairs. "Crews have secured the site, the fire department is on the scene and crew members are now working to safely shut in the well."

BP has depressurized the drilling site in an effort to control the release, the state said. BP said Friday afternoon it was shutting down the well.

"A full assessment of the impacted area will be made and initial remediation plans developed once the well is secured," Clanton said in a Saturday statement.

However, a DEC report issued Saturday said "the situation is not safe yet for responders to access the area and confirm that there have been no impacts to adjacent tundra."

The source of the release, Well 3, is located on the Drill Site 2 gravel pad about 5 miles from the Deadhorse Airport. Deadhorse is an industrial hub for the Prudhoe Bay oil fields.

Response personnel will be unable to safely assess the area until the well is brought under control, the state said.

"The area that has been impacted is unknown at this time," DEC said. "There are no reports of any impacts to wildlife."

The DEC statement said BP will work with the state agency, the North Slope Borough and the U.S. Environmental Protection Agency to form a unified command to lead the response to the spill.

The state agency was working with BP and the Alaska Oil and Gas Conservation Commission, which regulates oil and gas wells, to investigate the cause of the leak, the statement said.