For years, officials in Billings have known that powerful cleaning solvents may be in the ground, near the site of a dry cleaning and laundry service. But testing and an effort in Congress has gotten a significant swath of the city designated a “Superfund” site to clean chlorinated, volatile organic chemicals and petroleum hydrocarbons.
EPA officials are beginning remediation work this spring to mitigate the toxic, odorless fumes in the central part of Montana’s largest city.
Representatives from the federal Environmental Protection Agency, along with state officials from the Montana Department of Environmental Quality, are looking to test homes, properties and businesses in the area “extending from Central Avenue approximately three miles, east-northeast, through several mixed-use neighborhoods and into downtown Billings.”
Officials told a group of concerned citizens at a meeting that solvents, often associated with dry cleaning or gas stations, were likely either dumped in cisterns or even disposed of in the ground. For decades, such disposal was common practice and not illegal. But those volatile chemicals have seeped into the ground and created a plume of concern because the vapors from these chemicals that can come through the ground and foundations of buildings can pose a long-term health risk to humans, including an increased chance of some cancers.
The remedy for the problem is straightforward, officials told the residents, a ventilation system, like those used to remove the radioactive gas radon from homes will do the same job keeping residents safe, but first they have to locate those properties to solve the problem.
“This is a pretty common and a very effective way to get rid of chlorinated solvent and petroleum vapors,” said Roger Hoogerheide, EPA Remedial Project Manager.
Drinking water contamination is not necessarily a concern for the environmental team working on the problem because all the water within the boundaries of the site is connected to city service lines. And officials are lesser concerned with wells that are used for landscaping instead of drinking.
The chemicals that pose a risk are a class of chlorinated solvents, commonly referred to as “PCEs,” or tetrachloroethene, trichloroethene, dichloroethene and vinyl chloride.
These chemicals can evaporate quickly and become a vapor that travels through air and soil. When it is released, it has the potential to enter groundwater and soil and is capable of traveling through them for distances, and the vapor can find its way to buildings and residences, seeping through cracks in foundations or sewer lines.
Those vapors can be inhaled by residents during the course of years. The risk is dependent on how much a person is exposed to, coupled with the time of exposure and how many times that exposure happened.
“A person exposed to low doses of these chemicals over a longer period of time might experience adverse health effects including neurological symptoms, immune effects, liver or kidney effects, or certain cancers,” the EPA said in an update to Billings residents. “While groundwater is not used for potable water, a person may be exposed to these chemicals if they drink water from a contaminated irrigation well or use contaminated irrigation water for recreational purposes such as filling a pool or kids playing in sprinklers.”
Eating vegetables or fruits grown with water from an irrigation source would likely pose less of a health concern, said officials, because of the limited concentration and limited exposure, if any.
New activity at the old site
Many people may have noticed some of the remediation work already happening. An old gas station at the corner of Central Avenue and 7th Avenue West was the focus of a soil remediation project.
However, problems were first noted more than 20 years ago when the Montana DEQ investigated and found PCE vapors in the area. Since then, the agencies have been working to treat the site, and in September 2021, the site was added to the EPA’s Superfund list.
The EPA will be collecting as many as 150 soil gas samples to “delineate the extent of soil gas in the subsurface.” It will also collect 60 samples in sewer pipes to see if they act as a pathway for the vapors. Also planned for this spring is an evaluation of as many as 50 homes and businesses in the site.
The pathways these toxic chemicals have taken could be different, whether they were simply dumped or have leaked from storage containers, but EPA officials stressed that when that happened, the danger of long-term exposure wasn’t well understood and it was not illegal at the time.
“It wasn’t illegal, maybe immoral, but not illegal,” Hoogerheide said.
Jason Fritz a toxicologist with the EPA said PCEs have both short and long-term exposure risks for people, but the size of the plume suggests that dumping or disposing the chemicals likely happened for years.
“This happened during the course of years to decades of dumping,” Fritz said. “It was pre-EPA and pre-Superfund and there were no laws to take care of it.”
He said unlike some other chemicals that have been labeled “forever compounds,” which remain indefinitely, PCEs will gradually break down, but not before long-term exposure could result in health hazards for humans.
He said that before designating a Superfund site, the EPA always considers a variety of options, including the choice of doing nothing, but given the research on chlorinated solvents, that wasn’t a good solution.
“It takes too long to degrade to get it back to elemental,” he said.
PCEs still exist and can be found in many household products, making proper disposal key, Fritz said. For example, many de-greasers that work getting oily substances off metal have PCEs and many fluids used in automobiles, for example, brake fluid also contain the chemicals, as well as glues and adhesives.
Unlike short-term exposure to high levels of chlorinated solvents, which include solvent intoxication that robs the brain of oxygen, causing nausea, dizziness or loss of focus, the longer-term consequences are what the EPA is more concerned about.
Cancers, including blood and liver cancers, have been linked to long-term exposures. However, non-cancer concerns include neurological symptoms such as delay in reaction times and even a change in color vision. Fritz said the most vulnerable population may be with women who are pregnant who seem to be the most sensitive or at-risk population.