When blasts ignited a massive fire at the Philadelphia Energy Solutions refinery last June, residents feared that the spectacular blaze contaminated the air they breathe.

Now that the U.S. Bankruptcy Court has approved the sale of the refinery complex to Hilco Redevelopment Partners, which wants to replace the refinery with a mixed-use development, concerns have shifted from air quality to contamination of the ground and the water beneath the two-square-mile property.

Indeed, a host of hazardous chemicals including cancer-causing benzene lurk beneath the land where crude oil was processed, stored, and shipped starting 150 years ago, according to government and corporate documents reviewed by The Inquirer.

Many compounds, especially benzene, have been found to exceed levels set by the state as acceptable for nonresidential property, according to reports compiled by the Pennsylvania Department of Environmental Protection and Evergreen Resources Group, which is handling a cleanup plan for Sunoco and has posted thousands of pages of documents online. Sunoco owned the refinery for decades until 2012, when it was sold to PES.

After the fire, PES was forced into bankruptcy, paving the way for Hilco’s $252 million bid to turn the area into a commercial and industrial site that would no longer include a refinery.

Records reflect pollution that occurred before, during, and after the Sunoco years, though officials say there’s no way to tell exactly who is responsible for each kind of pollution over the property’s long industrial history.

Sunoco, now a subsidiary of Energy Transfer LP, entered the refinery into a state program for cleanup in 2006. The cleanup plan is still being reviewed and applies only to environmental liabilities during Sunoco’s ownership. But some remediation has taken place over the years. Hundreds of wells have helped recover thousands of gallons of gas, oil, and other petroleum products from water beneath the ground.

So although the full extent of the contamination is still being assessed, documents show that more than a dozen tongue-tripping chemical compounds have leaked, spilled, or otherwise found their way into the ground or aquifers in excess of state safety standards.

Charles Haas, an environmental engineering professor at Drexel University, said the situation warrants caution, not alarm.

“Risk is based not just on concentrations of contaminants but on exposure pathways,” Haas said. “As far as I know, the public isn’t using that area for drinking water, or walking around on it.”

That risk, he said, could change depending on the complex’s future use. Digging foundations for new buildings, for example, could unleash vapors or could further contaminate groundwater, according to students in his class who are studying the site.

Alexa Ross, with Philly Thrive, a local activist group, said she still has concerns about potential benzene vapors she fears could be emitted from old tanks or other infrastructure, and has already been in contact with Hilco over its plans.

“We still have loads of concerns,” Ross said, including contaminated groundwater.

More than a century of pollution

The property likely has been contaminated ever since refining began there in 1870, a century before the Clean Water Act, the creation of the U.S. Environmental Protection Agency, and other regulations. Leaking lead-lined tanks and pipes, as well as petroleum processing, caused much of the damage, documents show.

In the past, some compounds flowed into the city’s sewer system, leading directly into the Schuylkill, which flows into the Delaware River. Most of those discharges were addressed starting in the 1990s. Though some contamination has reached the river, according to Elizabeth Rementer of the DEP, the “impact hasn’t been fully evaluated yet” and groundwater modeling will continue.

Refining petroleum — turning crude oil into such products as gasoline, diesel and jet fuel, kerosene, and home heating oil — requires the use of numerous chemicals.

The South Philly refinery processed up to 335,000 barrels a day of crude oil, using a vast network of tanks, pipelines, and a hazardous-waste facility, as well as a rail network that traces back to the 19th century, all offering opportunities for hazardous chemicals to spill, leak, and be dumped.

Benzene, a natural component of crude oil and other petroleum products such as gasoline, is linked with cancer and other diseases. Exposure to high levels, over the course of a year, is connected with immune-system and bone-marrow damage, bleeding problems, and a decrease in red blood cells.

Contaminated soil and water

The aquifer beneath the property isn’t used for Philadelphia’s drinking-water supply, which comes from the surface upstream on the rivers.

Some contaminated plumes of underground water are trapped in pockets of clay or sand. The DEP is concerned that others could migrate.

A portion of the Potomac-Raritan-Magothy aquifer runs beneath the property, and beneath the Delaware River toward New Jersey, which draws its drinking water from the aquifer.

Sunoco characterized contamination to the Potomac-Raritan-Magothy (PRM) from the refinery as minor, and said that it could not reach the rivers. Evergreen, the subsidiary handling the cleanup, said there are no residential or agricultural wells within a mile of the facility, so it posed no risk to users.

The DEP was not convinced. In one memo, an official wrote: “The evaluation of groundwater exposure pathways for potential human receptors is incomplete." The DEP mentioned concerns about the water supply in New Jersey in multiple documents.

“Contaminants of concern (COC) that exceed the department’s non-residential statewide health standards (NRSWHS) in deep groundwater medium are: chrysene, benzene, MTBE, naphthalene, cobalt, arsenic and manganese,” a DEP official wrote in 2011.

As for the aquifer that supplies drinking water in New Jersey? “Groundwater flow from areas of contamination in South Philadelphia to adjacent downgradient areas of New Jersey has the potential to affect supply wells drawing water from the lower aquifer of the PRM," the DEP official wrote.

Cleanup

Sunoco has cleaned up hundreds of thousands of gallons of groundwater containing light non-aqueous phase liquids (LNAPLs), which are contaminants from gasoline, diesel, and other hydrocarbons, according to the documents. The land isn’t considered clean enough for people to live on, but it’s appropriate for industry, according to state standards.

Sunoco has not been fined for any violations found at the complex during its operations, according to the DEP, because so many operations have contributed to pollution at the site over the decades.

Hilco has said it has an aggressive cleanup plan and will convert the site to a mixed industrial facility. However, how that cleanup could work with the Sunoco efforts remains unclear.

“At this time, it’s too early to determine exactly what agreements or plans will be needed moving forward," said Rementer, the DEP spokesperson.

Sunoco says it is still committed to the cleanup.

“We understand that this effort is important to those who live and work in the area, and we remain committed to fulfilling the agreements made between Sunoco/Evergreen and the Pennsylvania Department of Environmental Protection and the EPA," said Vicki Granado, a spokesperson for parent company Energy Transfer Partners. "Our cleanup efforts have been ongoing for decades and will continue after the sale of the facility.”