A natural gas pipeline company says it may be responsible for a contaminant that Brooke County fishermen found in Buffalo Creek earlier this week.

Bentonite, a clay-like substance used in drilling, was also found in the Ohio River, and state environmental officials are testing water samples for other possible chemicals.

The Intelligencer reports that MarkWest Liberty Midstream & Resources LLC issued a statement saying it's cooperating with regulators.

MarkWest says it had notified Pennsylvania officials about cloudy water in Blaine Township, Pennsylvania, near an area where a contractor had drilled a pipeline borehole.

There had been no activity at the site since May 2, but MarkWest says it learned late Tuesday that a foamy substance was reported several miles downstream.

It says it's committed to environmental responsibility.

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