Vapor contamination: DEQ indoor air monitoring
State health officials on March 1, 2018, notified the Oakland County Health Division that vapor from solvents associated with the dry cleaning and automotive industries was discovered in Franklin Cleaners and other businesses located at the Franklin Village Plaza, on Franklin Road in Franklin. As a result, several of the businesses were encouraged to temporarily and voluntarily close or be forced to be evacuated.
"We are notifying the public out of our duty to inform of potential health risks," Oakland County Medical Director for the Oakland County Health Division Pamela Hackert said at the time of the business closures. "Not everyone gets sick from breathing these vapors. Health risks vary dependent on the level and length of exposure in addition to the health of the individual. If you have health concerns, talk to your doctor."
Further investigation revealed the vapor contamination was coming from a storage tank found in a crawl space of the building that contained at least 45 gallons of an unknown volatile organic compound (VOC). The discovery led to the mandatory temporary closing of five shops at the plaza.
Air quality testing indicated the solvents included tetrachloroethylene, a chemical used in the dry cleaning and automotive industries, both as a stain remover and metal degreaser. Also called tetrachloroethene and perchloroethylene, the chemical is commonly referred to as PCE. Investigators also discovered the presence of trichloroethylene, or TCE, another chemical associated with dry cleaning and degreasing, as well as petroleum byproducts from a former gas station at the location.
The chemicals may contaminate soil and groundwater. Vapor from the contaminated soil may then enter the air inside of a building and cause harm to the inhabitants breathing the air. Long term exposure to the chemicals may lead to various health issues, including color vision loss; changes in mood, memory, attention and reaction time; birth defects; and some types of cancer.
While the chemicals are commonly used in the dry cleaning industry, health officials said neither PCE or TCE are used at the Franklin Village Plaza location, as the store sends items to another location for actual dry cleaning. The Michigan Department of Environmental Quality (DEQ) has stated Franklin Cleaners is not responsible for the vapor intrusion as they conduct dry cleaning or store chemicals on site. Rather, officials with the DEQ said the contamination was linked to businesses that had operated at the location more than 30 years earlier.
The discovery was a result of the DEQ's ongoing statewide efforts to investigate vapor intrusion and indoor air quality resulting from known contamination sites.
Vapor intrusion occurs when gases from volatile chemicals in contaminated soil and/or groundwater move through the soil and into buildings through cracks in the floor, walls, and gaps around service pipes. In outdoor air, these vapors are often diluted to harmless levels. When trapped in an enclosed space like a home or building, these vapors can collect and impact the indoor air quality and pose a risk to health.
"We knew there was an old gas station there and a former dry cleaner," said Paul Owens, district supervisor with the DEQ's Remediation and Redevelopment Division. "We found some contamination and these chlorinated solvents associated with an old dry cleaner."
The DEQ began taking indoor air samples at the Franklin Village Plaza site in February, but the department's investigation into contaminants at the site started more than a year earlier.
Investigators with the state's environmental department had been looking into potential contamination at the plaza since July 2016. The DEQ at that time collected and analyzed 35 private drinking water supply samples. While none of the samples exceeded state thresholds for drinking water contaminants, environmental regulators continued to suspect contamination at the site due to past business uses at the location in or around the 1930s through 1970s.
In May of 2017, the DEQ requested and received permission from property owners to access the site to conduct further sampling, including soil borings, water-monitoring wells and air pins to measure contamination vapor in the air. In October, the DEQ finished surveying the subsurface or contaminants. In late 2017, the DEQ collected about 80 soil samples, 27 groundwater samples and 23 vapor samples. In January 2018, the DEQ collected water samples from the Rouge River, and evaluated additional soil and groundwater samples near the plaza.
"Beyond the soil and groundwater, we did soil gas samples underneath and around the building," Owens said. "That had high levels. The next step was to do indoor air quality samples, and those showed problems."
In February 2018, the DEQ collected indoor air samples from four of the five businesses in the Franklin Village Plaza that were later forced in March to evacuate.
Despite the discovery, business owners, staff and customers were unaware they had been exposed to potentially harmful vapors. Instead, the work was the direct result of a push by the DEQ to investigate more than 4,000 sites throughout the state where there is a potential for vapor intrusion, including more than 400 in Oakland County.
Despite the health risks associated with vapor intrusion sites, the vast majority of potential sites are unable to be tested due to a lack of funding.
"It's a workload issue," Owens said. "In Oakland County, we have about 530 sites that could have potential for vapor intrusion risk. We don't have resources to investigate or look into all of those.
"There are about a dozen we are working on where the risk may be higher, and we are working on those."
While health and environment regulators have known for decades about the dangers of vapor intrusion, toxicologists have just gained a new understanding about PCE and TCE in recent years, spurring a push for locating and mitigating sites contaminated with those solvents.
"Part of it has to do with what we know about vapor intrusion that we didn't understand before," Owens said. "The levels of TCE and PCE are lower now than 10 or 20 years ago."
Michigan's threshold criteria for vapor intrusion of PCE and TCE has been lowered in recent years, with the state's official vapor intrusion guidance document currently being updated. The update to the state's vapor intrusion criteria comes at the same time as a push to investigate potential sites.
"That push came from 2016, as our knowledge of toxicology of solvents and the way it transports through the ground increased, and our realization that current science says there is lower levels that can be an inhalation risk," said Josh Mosher, assistant division director for the DEQ's Remediation and Redevelopment Division. "It's a much more difficult pathway to find than say, drinking water, where you can put someone on bottled water until you figure it out. It's hard to tell someone not to breath.
"You have to do these quickly, and if vapor is found at certain levels, you have to evacuate people from homes or businesses."
The DEQ officially recognized the vapor intrusion pathway in 1998, and formally promulgated generic criteria for vapor intrusion under Part 201 of Michigan's Natural Resources and Environmental Protection Act in 2002, which governs the cleanup and redevelopment of contaminated properties in Michigan. Part 201 addresses liabilities associated with owning and operating contaminated properties in Michigan while simultaneously encouraging their redevelopment and reuse.
Groundwater and/or soil concentrations of volatile organic compounds, such as TCE and PCE, are currently used to determine whether the risk of contaminants in indoor air is acceptable. Exceeding the criteria in one or more samples at a location is sufficient to require remedial measures under Part 201 of Michigan's Natural Resources and Environmental Protection Act.
In 2010, the Michigan Legislature amended Part 201 to, among other things, require the DEQ to update the cleanup criteria rules to take into account recent scientific information. In 2014, a Criteria Stakeholder Advisory Group was created to make recommendations. Additionally, four Technical Advisory Groups were formed to address specific technical elements of the revised cleanup criteria.
In November of 2016, the DEQ identified more than 4,000 sites where potential vapor intrusion may be occurring. Of those some 4,000 sites, the DEQ identified about 402 in Oakland County. Of those 402 potential sites, there are 13 in Birmingham; 12 in Bloomfield Township; two in Bloomfield Hills; eight in Rochester; and 16 in Rochester Hills.
Officials with the DEQ said potential vapor intrusion sites listed in 2016 don't necessarily have a vapor intrusion pathway. Instead, those locations on the list may have had current or past uses that are typically associated with vapor intrusion, or may have known contamination that could be associated with vapor intrusion.
Meanwhile, the federal Environmental Protection Agency (EPA) in December 2016 included PCE and TCE to its list of 10 chemicals that are undergoing risk evaluations under the Toxic Substances Control Act. The evaluations are intended to determine whether a chemical presents an unreasonable risk to health or the environment under conditions of use. As part of the process, the EPA must evaluate both hazard and exposure, excluding consideration of costs or other non-risk factors.
Both PCE and TCE are already subject to various state and federal regulations and reporting requirements. For instance, PCE falls under the federal Toxics Release Inventory as a reportable chemical under the Emergency Planning and Community Right to Know Act, meaning that certain quantities at a location must be reported to the county's emergency management and preparedness department, which then shares that information with the state. Both chemicals are also regulated under the Clean Air Act and the Safe Drinking Water Act.
In January 2017 and December 2016, the EPA published two proposed rules under the Toxic Substances Control Act, including one to ban commercial use of TCE in vapor degreasing, and the other to ban use of TCE in commercial and consumer aerosol degreasing and as a spot cleaner in dry cleaning. The actions means the EPA is proposing to prohibit commercial use of TCE for those purposes.
The EPA plans to issue one final rule addressing the TCE uses in both proposed rules. Meanwhile, the EPA is still in the processes of conducting risk evaluations on both TCE and PCE.
Considered a human carcinogen, the U.S. accounted for 24 percent of the global demand for TCE in 2014, second only to China, which accounted for about 52 percent of the global demand. About 83 percent of TCE is used as an intermediate in the production of certain refrigerants. About 14.7 percent of TCE is used as a degreaser for metal parts, with only about 1.7 percent used as a spot remover in dry cleaning, as well as aerosol products, according to an EPA report published in 2017.
The use of TCE as a dry cleaning solvent lasted from the 1930s to the 1950s, when it was found to attack cellulose acetate dye in clothing. However, it's still used as a textile spot remover, including in dry cleaning products to remove water and oil-based stains.
TCE has various other uses, including use in the decaffeination of coffee. While a ban on using TCE in food processing was proposed in 1977, it wasn't enacted. Among TCE's varied uses, it was also used as a solvent for the extraction of natural fats and oils such as palm, coconut, soybean, olive, corn and other foods until 1952.
Exposure to TCE is most common by breathing vapors in homes and buildings from contaminated soil or groundwater beneath them. TCE vapors found underneath or near a building can enter the air of a building and reach harmful levels, according to the Michigan Department of Health and Human Services.
Women who are or might be pregnant are particularly advised to avoid exposure to TCE, which may cause serious health problems for the fetus.
While health experts say it only takes a few days for an average person to get rid of TCE in their body, chronic or short-term exposure may be problematic.
A risk assessment of TCE by the EPA published in 2014 identified cancer risk concerns and short-term and long-term non-cancer risks for worker and occupational bystanders at small commercial degreasing facilities and dry cleaning facilities that use TCE-based solvents. In all cases, the main route of exposure is inhalation of the chemical. However, the EPA found TCE to be carcinogenic to humans by all routes of exposure.
The findings, the EPA states, were based on strong cancer epidemiological data that reported an association between TCE exposure and the onset of various cancers, primarily kidney, liver and immune system, such as non-Hodgkin lymphoma. Additional studies, including rodent cancer studies, support TCE's classification as carcinogenic.
Non-cancerous health effects indicate adverse health effects to the kidneys and liver, as well as the nervous system, immune system and reproductive system.
PCE, also commonly called Perc, is a colorless, nonflammable organic solvent used in dry cleaning, degreasing and a process solvent for desulfurizing coal. It was also used extensively as an intermediate in the manufacture of chloroflurocarbon (CFC) refrigerants until most CFCs were banned in 1995. PCE's primary use is not as a chemical intermediate, specifically as the raw material for hydrochlorofluorocarbons (HCFCs), and produced as a co-product, along with other chlorinated hydrocarbons.
The EPA considers PCE to be a likely human carcinogen, based on experimental animal studies. Rats and mice dosed with PCE orally or via inhalation exposure had increased incidences of kidney, liver and lymphoid tumors. Human studies also have suggested an association between PCE exposure from drinking water and cancer. Short-term exposure can result in irritation to the skin, eyes and upper respiratory tract. Headache, dizziness, drowsiness, ataxia and mood changes have been reported from acute inhalation to PCE. Higher levels of PCE exposure may result in coma and seizures.
The EPA states that dry cleaning workers exposed to PCE had deficits in short-term memory tests for visual designs, reaction times, perceptual function, attention and intellectual function.
While the two chemicals aren't the only ones associated with vapor intrusion pathways, they are two of the most commonly linked to the issue, Owens said. And, despite the risks posed by vapor intrusion sites, Michigan currently lacks a dedicated funding source to address the problem.
"We do have something called Refined Petroleum Funds, which goes toward old gas stations or petroleum Leaking Underground Storage Tank (LUST) sites," Owens said. "Those do cause some vapor intrusion problems, but unfortunately, a lot of vapor intrusion problems come from these chlorinated compounds, and we can't use that funding unless (the contamination) is co-mingled."
About one cent per gallon of gasoline sold in Michigan is used to fund investigating and mitigating leaking underground storage tanks that involve petroleum products. The state estimates about 7,200 such sites across the state. Rules to address petroleum contaminated sites is found under Part 213 of the Michigan's Natural Resources and Environmental Protection Act. However, funds from the Michigan's Refined Petroleum Fund can't be used for Part 201 sites unless petroleum-based products are also suspected at a location.
"If it's just a chlorinated compound release alone, we have to use a different funding pot," Owens said.
Owens said the investigation into vapor intrusion at the Franklin Village Plaza originated from a former gas station at the site, which allowed the department to use money from the state's refined petroleum fund.
"We did an investigation there to see if there were threats because we knew there were drinking water wells in Franklin," he said. "Then we found this issue with chlorinated compounds when we were out there investigating."
In February 2017, Michigan Gov. Rick Snyder proposed providing about $4.9 million for the state's Vapor Intrusion Program to replace exhausted funding formerly provided by the state's Clean Michigan Initiative (CMI) bond, which provided funding for the state's Part 201 sites.
The legislature provided about $1.3 million to fiscal year 2016-17 for the program, which supported about four full-time positions and contractual work to address some 4,000 potential vapor intrusion sites.