Hazardous chemicals in bay sediment near San Francisco's single remaining large power plant threaten the health of people and marine life, yet Pacific Gas and Electric Co. has been slow to investigate the problem, according to Port of San Francisco officials and city leaders.

The carcinogenic chemicals are byproducts of coal tar, a thick, dark, gooey substance left over from industrial uses at the eastern waterfront site. Much of them came from the manufacturing of gas that lit the city's homes and street lights in the 1800s and is not related to current power-generating operations.

The large coal tar deposits and other compounds pollute the soil onshore, and the tar has oozed from the shoreline into the bay over the years.

The company knew about the contamination for at least a decade and cleaned up some of the land and covered up other sections so it didn't pose an immediate health risk to people who work there, according to a Chronicle review of documents provided by PG&E and interviews with utility officials.

Yet independent toxic chemical experts say they have no doubt that the contaminants have been migrating from the soil to the bay sediment for years in concentrations that are unsafe for marine life and humans. PG&E only now is starting to fully study that issue.

The area is not a popular swimming spot, but people have long fished from a nearby pier and the shoreline. Among other potential problems, eating fish exposed to the chemicals could cause cancer in people, the experts say.

"All I can say is that I wouldn't eat any of the fish myself," said John Fetzer, a former research chemist for Chevron and an expert in the coal tar contaminants called polycyclic aromatic hydrocarbons or PAHs. "Even if the fish don't develop cancers, they accumulate them (the chemicals) in their fatty tissues."

Delay alleged

Port of San Francisco officials want PG&E to move more quickly to analyze the sediment and remove it if necessary. They are calling for state regulators to impose strict deadlines.

Sophie Maxwell, the San Francisco supervisor who represents the area, said PG&E has dragged its feet.

"When PG&E wants to do something faster, they manage," Maxwell said. "It's always an excuse to say that you're following the regulations, but when you want to move on something more quickly, you streamline the process."

PG&E representatives say they are cooperating with the port and want to resolve any environmental problems. Based on previous studies of the shoreline, the company does not believe that the coal tar-related chemicals are moving into the bay. They acknowledge, however, that without more research, there is no way to know for sure.

"We're trying to understand the source of the contaminants in the samples," said PG&E spokesman Joe Molica. "We're trying to characterize where the contaminants came from so that we can come up with a cleanup plan ... and to understand what impact our previous operations created."

The port owns property on and off the shore east of the Potrero Power Plant site and at Pier 70, which abuts the property to the north. The port has plans to eventually develop the long-dormant Pier 70 area with offices, restaurants, shops and parks.

Port officials say that coal tar-related chemicals were found on their side of the property line and believe that they traveled in groundwater from the power plant.

Toxics found in bay

While state regulators note that roughly 125 former manufactured-gas plants exist in the state, the San Francisco site is the only one located on a natural shoreline. Some other old plants are on waterfronts, but they have bulkheads that act as barriers between the polluted upland soil and the water.

Fetzer was hired by the city to review reports completed by environmental consultants in 2000 and 2001. He said those reports showed extremely high levels of toxics in the offshore mud.

"The levels in the sediment were roughly 100 times what the Environmental Protection Agency suggests for soil and drinking water," Fetzer said.

Contamination has likely increased over the years because the coal tar-related compounds continue to seep into the bay, he said.

"You have almost an infinite supply of stuff leeching out of there unless something gets done," Fetzer said. "What's on the site will keep going out into the bay."

The port argues that PG&E has tried to downplay the relationship between coal tar under the soil and similar contamination in the bay sediments.

"The connection between the onshore contamination and sediments seems like a logical conclusion," said Jay Ach, manager of regulatory and environmental affairs for the port.

PG&E's Molica counters, however, that other industrial operations could be to blame for any chemicals found in the bay.

State water pollution regulators are satisfied that PG&E is making reasonable progress in addressing the problem, so they have not demanded timelines for studies and possible cleanup. Port officials want specific deadlines.

PG&E responsible

Although PG&E is legally responsible for the coal-tar cleanup, it sold the land and power plant in the late 1990s. The diesel-burning plant is now owned by Mirant Corp. and is the center of a long-standing dispute among city officials over whether it should be closed. Some officials have pushed for cleaner, city-owned generators that would still run on fossil fuel. Others have called for retrofitting the current power plant and keeping it open while alternative power options are explored.

In addition, Supervisor Maxwell joined then-Board of Supervisors President Aaron Peskin and City Attorney Dennis Herrera last month in writing to the San Francisco Regional Water Quality Control Board. They threatened legal action if the board did not stop Mirant from using a cooling system that kills hundreds of thousands of fish larvae, discharges heated water into the bay and stirs up toxics in the sediment.

The water board has said that it has no immediate plans to do so. Mirant has said it is working cooperatively with the regulators.

Stephen Hill, the toxics cleanup division chief for the water board, said he believes that the stance taken by the port, Maxwell and other city leaders to PG&E's cleanup efforts relates to the debate over closing the power plant.

"The back-and-forth between the city and PG&E is part of the adversarial issue," Hill said. "A lot of people in the city want the plant to be shut down."