The state Department of Environmental Protection has fined Murrysville-based DeCesare Corp. $25,000 for violation of the Clean Streams Law at one of the firm's work sites.

The DEP levied the fine after work on the San Ria Court development on Weistertown Road, Murrysville, caused storm water runoff to enter Steels Run, a cold-water fishery that has been designated a high-quality stream.

Studies by the Westmoreland Conservation District from 2004, 2006 and 2007 show that DeCesare Corp. failed to implement controls that would have averted runoff into Steels Run.

"Development cannot come at the expense of Pennsylvania's water resources," said Kenneth Bowman, the DEP's southwestern regional director. "Working with our partners in the county conservation district, DEP is committed to enforcing the regulations and laws that protect the commonwealth's streams and rivers."

According to a DEP press release, storm water runoff from sites where surface soils are bare can speed up erosion and cause sediment to reach waterways where aquatic life is at risk.

Sediment covers fish eggs and underwater gravel nests, clouds and pollutes water, kills plant life, decreases oxygen in the water and wreaks havoc on the aquatic food supply.

DEP spokeswoman Helen Humphreys said the sediment in Steels Run posed a particular danger to fish that thrive in cold water, such as trout.

Ms. Humphreys also said the fine was issued as a consent order, so DeCesare Corp. has agreed to pay the fine.

DeCesare Corp. Chief Executive Officer Ted DeCesare did not return calls.