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How Do We Decide When a Chemical Is Deadly?

When state and federal regulations for contamination differ, the responsibility falls on citizens to navigate the risks.
Third Sister Lake in Michigan.

Third Sister Lake in Michigan.

One unseasonably warm February morning in Ann Arbor, Michigan, Wesley Pate received a knock on his door. When he answered, Pate was greeted by Dan Bicknell, who runs the environmental consultancy Global Environmental Alliance. Bicknell had only one question: Was Pate aware that his well water was contaminated with the carcinogen 1,4-dioxane?

Pate’s family had been renting the home for over two years; he says they were not aware of the chemical. They’d been using the water for all their day-to-day needs: cooking, bathing, making infant formula.

Just like that, Pate found himself trying to move his wife and three young children out of their house — no matter what the cost.

“Since I’ve been told this, it’s like I’m on high alert, waiting for something to happen, where I’ve got to rush someone to the hospital,” Pate says.

Although no one from the state had knocked on Pate’s door since the family began renting the home, his well water measures significantly below Michigan’s current groundwater clean-up standard for 1,4-dioxane, so there was technically no requirement to do so. On the other hand, the well water measures significantly higher than what’s recommended at the federal level by the Environmental Protection Agency.

How can such a large difference exist between federal and state standards?


Just a few miles away, Third Sister Lake was once a beautiful, spring-fed body of water, so clean that it was originally designated as a potential source for drinking water for Ann Arbor, according to the the University of Michigan School of Natural Resources and the Environment.

In 1984, Bicknell, an Ann Arbor native, returned to the area to attend graduate school at the University of Michigan. As a child, he’d swam in Third Sister Lake, though that was against the rules because the lake was used for research by the university. Now as a graduate student, he once again snuck in for an occasional swim. It was during one of those leisurely swims when Bicknell found what would set off the 30-year pollution clean-up problem that continues to this day.

Gelman Sciences sat adjacent to the forest that’s home to the lake. The company produced filters to detect water and air pollution. It used the solvent 1,4-dioxane in one step of the production process. To dispose of the chemical, Gelman sprayed it over its lawns and pumped it into unlined lagoons, according to the City of Ann Arbor.

“I noticed that there was this creek that was going from the [Gelman Sciences] property into Third Sister Lake,” Bicknell says. “You could see on the spray irrigation system, which was on this flat plateau, that all the water was running down.”

The contamination of the lake was confirmed days after that 1984 swim. Bicknell was able to take a sample of the water back to the university to test it.

1,4-dioxane is a known carcinogen in animals and a likely human carcinogen, according to the EPA. The Department of Health and Human Services outlines some of the chemical’s effects on animals in its summary:

[L]aboratory rats that breathed vapors of 1,4-dioxane during most of their lives developed cancer inside the nose and abdominal cavity. Laboratory rats and mice that drank water containing 1,4-dioxane during most of their lives developed liver cancer; the rats also developed cancer inside the nose. Scientists are debating the degree to which the findings in rats and mice apply to exposure situations commonly encountered by people.

Rita Loch-Caruso, a Michigan toxicologist and member of the Coalition for Action in Remediation of Dioxane, adds that, though recent research has expanded the understanding of 1,4-dioxane’s potential to cause cancer in humans, we’re still largely in the dark on the carcinogen’s effects on reproduction and fetal development. “That is a major concern of mine,” she says.

In 2010, the EPA’s Integrated Risk Information System assessed the criterion for 1,4-dioxane at 3.5 parts per billion — or ppb, a technical term for the number of units of mass of a contaminant per 1,000 million units of total mass — for an excess cancer risk of one in 100,000, meaning that’s the level at which an additional case of cancer is expected due to the exposure within a population of 100,000.

Many consider IRIS the “gold standard” of toxicity data. Michigan’s generic groundwater clean-up standard for dioxane is 85 ppb, the highest of the states that have a standard, and it’s stayed 85 ppb for more than five years after the EPA’s 3.5 ppb recommendation. In March, the Michigan Department of Environmental Quality announced that it would finally propose to tighten the standard to 7.2 ppb, ideally in April.

Bicknell’s test revealed moderate levels of 1,4-dioxane in the lake water. He typed up a report and sent it to the local public-health department. At first, officials questioned Bicknell’s findings. Bicknell worked with residents on a petition to have their wells tested, and after the petition was presented, the county tested the wells. One of these wells had a concentration of 100,000 ppb.

In 1988, Michigan’s attorney general filed suit against Gelman to force a clean-up of the groundwater, and in 1992 the lawsuit was settled with a consent judgment. According to the City of Ann Arbor, the company agreed to pay the state over $1 million in damages and to begin a $4 million clean-up project. The consent judgment (which has since been amended) continues to guide remediation and includes monitoring and treatment guidelines.

How the company has done with the clean-up is a matter of whom you ask. In an email, a company spokesperson writes that “Gelman has consistently met its 1,4-dioxane groundwater contamination cleanup obligations as outlined in the Consent Judgment with the Michigan Department of Environmental Quality. In fact, Gelman has twice been recognized by the prestigious National Groundwater Association for excellence in the field of groundwater remediation in connection with its implementation of the Consent Judgment.” Citizen watchdog groups like Scio Residents for Safe Water disagree and point to a litany of disputes related to the judgment.

Wesley Pate’s water well measured at 17 ppb of 1,4-dioxane in 2016.


Bicknell knew the wells in this area of Ann Arbor tested high when compared to the EPA’s 3.5 ppb criterion. He also knew Pate’s well had tested at 17 ppb earlier in January 2016 through a report released by the company. He guessed that maybe 50 percent of the people in Pate’s area would know that their wells contained 1,4-dioxane. He was wrong. Of the several people he spoke to, none were aware of the 1,4-dioxane.

After he knocked on Pate’s door, Bicknell sent an email about his disturbing discovery to officials from the Michigan Department of Environmental Quality — the state agency responsible for conserving and protecting natural resources. (Bicknell also copied Governor Rick Snyder on that email.) That evening, Pate said he’d spoken only to Bicknell and two reporters. No officials had contacted him yet to help the family. State and county officials have since visited the Pates, and the house has been hooked up to the city water supply, according to local media.

The pollution continues to spread today alongside the growing “prohibition zone.” Portions of the city of Ann Arbor and nearby Scio Township are within this zone, which was expanded in 2011. Citizens must be hooked up to the city water supply in this zone; the use of wells is prohibited because groundwater is polluted with 1,4-dioxane, and homeowners are required to disclose this information to prospective purchasers.

What explains the dramatic difference between a standard of 3.5 and 85 ppb? A small degree of variation can be explained by how the values are calculated, based on state-specific expected exposure information and state-specific demographic data.

Many people who have been working on the Gelman Sciences pollution for decades now say the big difference between 3.5 and 85 ppb is political: These standards are set at the state level by legislators. Initially, in 1986, the state recommended 3 ppb as a safe standard. Then, in 1995, that standard was raised to 77 ppb after a series of polarizing legislative actions which “reduce[d] cleanup standards across the board” for polluters.

In the simplest terms, the 85 ppb standard first came about because Michigan then used different assumptions than their cohorts at the EPA in modeling risk, Loch-Caruso explains. In its re-calculation, the state is using more current assumptions and data. The process of attempting to tighten the standard to something closer to the EPA value has now taken over five years, and there is still no definite date for when the standard will be tightened.

“People on Elizabeth Road are drinking dioxane now, and have been doing so for a number of years.”

The 1,4-dioxane criterion is part of a state legislative package of revisions that looks at several hundred chemicals. Should the Department of Environmental Quality calculate updated criteria for all of these chemicals, a proposed administrative rule package would be released. A six- to nine-month review process would follow. While some parts of the process involve community feedback — a mechanism that stakeholders agree is important — other aspects seem to many to be unnecessarily unwieldy. “We don’t need to debate the dangers of dioxane,” says Roger Rayle, another Ann Arbor resident who has been involved in the issue since the 1990s. “The EPA has spoken on that. Why has it taken the state five years to accept that?”

Once the package has been reviewed according to this process, it goes to the state legislature. Stakeholders have been careful to include industry representatives in the behind-the-scenes work to generate legislative buy-in, but there’s no guarantee. The Michigan legislature has made headlines recently with some of its more radical decisions and its lack of transparency.

The Department of Environmental Quality’s Bob Wagner has emphasized the distinction between the EPA’s and the state’s numbers. “In Michigan, we have generic clean-up criteria, which are, by law, the standards you must meet,” Wagner says. “In our case, we are doing an update that the legislature directed the department to do for 310 chemicals. And so, it’s a little bit of a lengthy process, but once the criteria are finalized and promulgated, they will be law, whereas at the federal level they still are just a screening level. It’s a different process, and different result.”

Another Department of Environmental Quality official emphasizes the consent judgment. The 85 ppb is part of the consent judgment that guides remediation, so when Michigan’s criterion is tightened to 7.2 ppb, the consent judgment won’t be altered to match. Local county and city officials anticipate that the company won’t remediate to the new standard voluntarily and that another lawsuit might be needed.

Gelman Sciences has been acquired twice, first by Pall Corporation in 1997, and then again by Danaher Corporation in 2015. A company spokesperson did not directly address the question of how the company would react to a possible new, lower criterion. In an email, he writes that Gelman Sciences “remains committed to fulfilling its cleanup obligations in accordance with all applicable legal requirements.”

“By state law, pollution does not need to be cleaned up; it only needs to be controlled in terms of exposure to humans,” Loch-Caruso adds. “So the state of Michigan sets a standard, a concentration level that they consider acceptable for human exposure. And the remediation is only to limit human exposure to below that level. So that means putting up a fence or paving a parking lot, or whatever it might be that meets the law, as long as it limits the human exposure to below that level.”

Meanwhile, people are drinking chemicals. In addition, there are other implications, including financial ones. If the EPA finds that a chemical is less toxic based on its research, but the state is legislatively bound by a more stringent standard, the state could be spending money and resources to clean something up more than is needed according to latest federal findings. Or, as Bicknell calls it, “wasting state and private party funds on unnecessary remediation.”

And the public-health concern remains: In light of such dramatic inconsistencies between federal and state recommendations, how can citizens be sure that their state government is protecting their health?


Over the past 30 years, as the pollution has continued to spread in the Ann Arbor area, the prohibition zone has expanded along with it. More wells have also been contaminated. Washtenaw County health officials said that they work together with the Department of Environmental Quality to routinely monitor drinking water wells located along the contamination plume’s expanding boundaries. “In addition to the 27 wells we regularly sample, we worked with the DEQ to sample 100 additional homes in 2014. None of the 127 sampled wells had any detectable concentrations of 1,4-dioxane. Washtenaw County Environmental Health is currently working with the DEQ to sample another 38 homes in 2016 in areas where the plume looks to be migrating,” officials write in an email.

While officials cite these monitoring statistics, Bicknell returns to the impact on individuals. “People on Elizabeth Road are drinking dioxane now, and have been doing so for a number of years,” he says. (The DEQ’s residential well reports from 2015 show that a well on Elizabeth tested at 2 ppb.) At a recent public meeting of CARD, two concerned mothers of young children who live near the plume but aren’t on the county’s list said they’d spend their own money on testing their wells. As for the Pate family, they’ve recently retained an attorney, local media reported, though defendants, if any, have not been named.

Bicknell’s experience as an enforcement officer for the EPA’s Superfund — its program for the clean-up of hazardous waste sites — has come in handy in Ann Arbor. He compares the DEQ to a bad contractor, arguing that they’ve failed in many aspects of the remediation process, from contingency planning (there isn’t a contingency plan in case the plume gets to the city’s main drinking supply), to lax enforcement (the failure for over five years to tighten the Michigan standard from 85 to something closer to EPA’s 3.5), to community communications (see: Wesley Pate). “The shortfalls on this are unparalleled,” Bicknell says. DEQ officials have framed some of these shortfalls as a consequence of the legislative and lawsuit constraints under which they must operate.

In Ann Arbor, stakeholders — including city, township, and county officials, as well as concerned citizens — take different tacks in describing the deficiencies of the remediation as handled by the DEQ. “I don’t want to criticize the staff at the DEQ,” says Yousef Rabhi, a county commissioner who has worked as a liaison to CARD. “I think that the staff at the DEQ are oftentimes people who want to do the right thing, who believe in wanting to create a community that is safe from an environmental perspective and is healthy for its residents … but the DEQ overall is broken, and it is because, simply put, corporate interests run the DEQ. They are not operating with the best interests of the public in mind.”

Bicknell has been working behind the scenes to educate local stakeholders about petitioning the EPA for Superfund status. Bicknell says the Gelman pollution would easily meet the Superfund site designation requirements, based on his calculations.

Recently Michigan Radio reported on the Superfund option, quoting a local official who called this possible move “the nuclear option.” Bicknell agrees that the Superfund option is “not the most preferred option,” but he strongly believes that “it’s the only option left.” Rabhi says that it’s unfortunate the problem has reached this point. “I think that we just need more options available to us,” he says. “Because my top priority as a locally elected official who’s directly on the ground working with these constituents that are impacted by this problem — my top priority is human health.” (A Gelman spokesperson could not be reached for comment regarding the possible Superfund petition.)

The community’s frustrations and disappointments over the course of the past 30 years are also fueling the fire. The Superfund program recently held its 35th anniversary of “managing the cleanup of the nation’s worst hazardous waste sites and responding to local and nationally significant environmental emergencies,” according to the EPA’s website. It is easy to see why a community that has struggled for a remediation effort to protect public health might find the Superfund option appealing.

In an email exchange, an EPA spokesperson writes that, when developing Superfund site risk assessments, “the EPA uses the best science available for contaminants being evaluated. If a contaminant’s health assessment information is available in EPA’s [Integrated Risk Information System], then this information generally is considered the best science available.”

“In my experience, the lack of using an IRIS value manifests a poorer quality remediation level by the states,” says Bicknell, who’s run across similar issues during his time with the EPA in Florida and Michigan. “The Florida Department of Environmental Protection has the same rules updating problem as DEQ in the establishment of groundwater clean-up requirements.” Bicknell cites his 2013 summary of the difference between two chemicals of concern at a Florida “brownfield area,” or an area marked as potentially hazardous. Loch-Caruso, the toxicologist, agrees. “Especially if you look at historical sequence of events in risk modeling in the state of Michigan, I think the people of Michigan will be better protected by relying on EPA risk assessment,” she says.

Bicknell notes additional financial implications. “The use of IRIS values by the states would eliminate the redundant expenditures by the states on staff to access chemical toxicity constants,” he says. The EPA staff also tends to be better-resourced when it comes to conducting research and related work to determine the standards. “Generally, the EPA staff is much better able to evaluate chemical toxicity than state staff,” he says.

“As with many pollutants, who can regulate 1,4-dioxane depends on where and how the chemical manifests itself,” says Philip Rocco, a researcher studying the effects of institutional fragmentation on public policy at the University of Pittsburgh’s Health Policy Institute. He explains that, unless pollutants are regulated by a law like the Safe Drinking Water Act (or, often, by legislation revising the Act), the federal government’s role is highly advisory. In such cases, “frequently cash-strapped states must pick up the slack. This means that federal regulatory science outpaces what states can do.”

Rocco says that whether the Superfund solution might be effective for the Gelman site is a complicated matter. “Our research shows remediating sites is a complex process and probably won’t address the larger issue of the need for Congress to take action,” he says.

How can the value determined by “best available science” vary so drastically from the state’s criterion? In the end, the inconsistencies aren’t just data discrepancies; they’re directly impacting people’s lives.

Pate didn’t know about his water testing at 17 ppb, but he says that even knowing the value he’d choose to live elsewhere, especially with the kids. It wouldn’t matter to him that it was below the state criterion. “I wouldn’t have even moved into that house if I had known,” he says. “Not with my children. I mean, my children are my first priority.”