Duquesne Light Company Crews Searching for Leak in Underground Transmission Cable in North Side

PITTSBURGH — On Monday afternoon, April 29, Duquesne Light Company (DLC) system operators learned that an underground transmission cable on the North Side of Pittsburgh was leaking a non-toxic, clear liquid used to cool down and insulate underground cables as they safely deliver reliable power. DLC crews have been working around the clock to identify the source of the leak and have taken measures to limit potential environmental impact, including significantly slowing the rate of the leak and scanning the rivers both at the surface and underwater. Currently, DLC estimates approximately 12,000 gallons of fluid, about 14% of the cable contents, have escaped.

Industry and environmental experts, as well as various local resources, have been brought in to assist in the ongoing effort. Crews are digging in the areas of Seymour Street and River Ave. today to continue pinpointing the source of the leak. No power outages or injuries have occurred as a result of this incident.

“DLC crews continue to locate the source of the leak and are working to mitigate risks whilekeeping power flowing to our customers,” said John Hilderbrand II, vice president of operations for DLC. “We expect to have regular updates throughout the coming days and appreciate everyone’s patience and support.”

About the Substance

• Commonly referred to as dielectric fluid, the leaking substance is a clear, mineral-like liquid that presents a glossy-like sheen and is non-toxic to the public.

• It is non-flammable and non-combustible.

• In large, concentrated quantities, it may impact aquatic life.

• It has a faint mineral oil smell.

Current Response

• DLC is working with local partners, including Pittsburgh Water and Sewer Authority and Allegheny County Sanitary Authority, to identify and investigate areas where the liquid may be if it has entered any rivers.

• The company is isolating areas along the cable line (which stretches from Brunot Island to the Strip District) to determine potential leak sources.

DLC proactively notified local and state agencies, including the Public Utility Commission, Pittsburgh Emergency Management, Allegheny County Emergency Services, Army Corp of Engineers, U.S. Coast Guard and, Environmental Protection Agency and Department of Environmental Protection.

If area residents notice a clear, sheen-like substance on the rivers or entering nearby waterways, they should notify the National Response Center at 1-800-424-8802.