The Delaware Department of Natural Resources and Environmental Control’s site investigation and restoration section is currently investigating 34 past and present dry cleaning sites in the Dover area. These sites are being investigated for contamination caused by a chemical called perchloroethylene, or PERC for short, said James Poling, Brownfields administrator for DNREC.
Brownfields is a program within the site investigation and restoration section of DNREC that seeks to clean up and redevelop contaminated sites that are underutilized, abandoned or vacant.
PERC is a colorless, nonflammable liquid that is used most commonly in dry cleaning, textile processing and metal cleaning. The potential problem of PERC has been on DNREC’s radar for several years, Poling said.
“We used federal dollars to do assessments of areas or industries,” he said. “I decided to look at the topic of dry cleaners. We know that the industry uses this stuff called PERC, and it’s likely a probable carcinogen. In Delaware, lots of little strip mall have a liquor store, a dry cleaner and a super market.”
At this point, 32 of the 34 sites in the Dover area have been visited by consultants hired by DNREC − 10 have been identified as active, six are inactive and 16 remain unknown. Those unknown sites are those that SIRS has identified as being a past location of a dry cleaner through historic record or word of mouth, but SIRS has not been able to confirm that information.
The ultimate goal of the project is to study the effect of PERC, Poling said.
“As we look at dry cleaners and other industries that use this chemical we are trying to see if there is a substantial nexus between the cleaning industry and harm to the environment or human health,” he said.
There are several ways that PERC can enter the environment − either through accidental spills, through a fire or other disaster destroying a dry cleaning site or through dumping. Up until 1970, it was not illegal for people to dispose of their waste at their facility.
Once PERC enters the environment it can move fast, Poling said.
“It is a dense solvent and can move fast through the sandy soil that Kent County and Sussex County have,” he said. “The PERC moves down and can start to get into groundwater.”
The chemical can be transferred from groundwater to drinking water if a well is fed through by an aquifer that the chemical has leached into. PERC can also be released as a gas. If it is released into soil that is rocky, the chemical can spread laterally in a shallow layer; as the chemical breaks down it can put off a gas that can rise up through the soil, Poling said.
Page 2 of 2 - “As the chemical decomposes it can move upward through any vent system, natural or manmade, such as a utility trench,” he said. “If PERC got into the soil, the gas could come up in the store beside the dry cleaners or 10 miles away.”
Because the chemical can move in various ways this issue has to be tackled on a case-by-case basis, Poling said.
“We have to treat each case individually,” he said. “We will test soils, see how deep water level is, where there are pathways and at the end who can be affected. Who are receptors?”
Angie Lee, who owns Brite Cleaners located in the Edgehill Shopping Center in Dover, said that dry cleaners shouldn’t be singled out.
“Auto body shops use PERC when they do oil changes,” she said. “Nobody has issues with that. Why is it only dry cleaners?
According to Lee, newer, high-tech dry cleaning machines have made using PERC much safer. The older machines still pose a threat, she said.
DNREC’s aim is to focus on PERC, Poling said.
“We try not to think of this as a dry cleaner initiative, but as a PERC initiative,” he said. “But clearly the most visible user of PERC is the dry cleaning industry, even though they may not use the most, quantity wise.”
DNREC’s investigation is still in the early phases, Poling said. He expects to have a report out on the matter by October 2014. Once the report is published, DNREC may be able to establish whether or not there is a need for concern.
For now, there is no reason to panic, Poling said.
“I’d be hesitant to say that this issue would set off any alarm bells,” he said. “We don’t want to get to a point where this is an environmental problem; we want to nip it in the bud. There have been no specific incidents. This is just good science and knowing what the issues are and beating them to the punch.”