NJ Clean Stream
njcleanstream.org
You’ve never heard of 1,4-dioxane — but it may already be in your water
There is a contaminant in New Jersey’s groundwater that most residents have never heard of. It hasn’t generated congressional hearings or the campaigns that PFAS has. It is not yet regulated at the federal level. But it is present in groundwater near industrial sites across the state — in concentrations the EPA considers likely to cause cancer. NJ Clean Stream is getting ahead of this one.
What is 1,4-dioxane?
1,4-dioxane is a synthetic chemical — a cyclic ether — that has been used in industrial applications for decades. It is a colorless liquid that dissolves in water completely and uniformly. Its most significant industrial application was as a stabilizing additive in 1,1,1-trichloroethane (TCA), a widely used industrial solvent and degreaser common in manufacturing, dry cleaning, electronics production, and military maintenance operations from the 1950s through the 1990s, when TCA was phased out under the Montreal Protocol. Because 1,4-dioxane was added to every batch of TCA, wherever TCA was used and disposed of, 1,4-dioxane was present as well.
1,4-dioxane has also been used as a processing solvent in pharmaceutical, cosmetic, and personal care product manufacturing, and as a byproduct of the ethoxylation process used to produce surfactants found in shampoos, body washes, and cleaning products. The result is a contaminant with an extraordinarily wide industrial footprint — present wherever TCA was disposed of over four decades, wherever certain manufacturing operations discharged wastewater, and wherever industrial landfills accepted TCA-containing waste.
What makes 1,4-dioxane so dangerous in groundwater
It is highly water-soluble and mobile. Unlike many organic contaminants that bind to soil particles, 1,4-dioxane moves through groundwater almost as freely as water itself. It does not adsorb significantly to soil or mineral surfaces, creating large groundwater plumes that extend well beyond the boundaries of contaminated sites.
It does not biodegrade readily. Under most natural groundwater conditions, 1,4-dioxane is resistant to the microbial degradation that breaks down many organic contaminants over time. It persists essentially indefinitely without active remediation. A plume that exists today will still exist decades from now if not actively treated.
It is not removed by conventional water treatment. Standard drinking water treatment processes — coagulation, sedimentation, filtration, chlorination — do not significantly remove 1,4-dioxane. A utility treating its source water with standard processes may be delivering 1,4-dioxane to customers’ taps at essentially the same concentration as in the source water.
Critical fact: 1,4-dioxane is also not removed by granular activated carbon (GAC) filtration — the workhorse technology for most organic contaminants. Water utilities that have installed GAC for PFAS or other concerns have not thereby protected their customers from 1,4-dioxane. These are independent treatment challenges requiring different technological solutions.
What 1,4-dioxane does to human health
The EPA classifies 1,4-dioxane as “likely to be carcinogenic to humans” based on animal studies showing liver and nasal cavity tumors, and mechanistic evidence supporting biological plausibility for human carcinogenicity. The EPA’s cancer risk assessment calculates that lifetime exposure to just 0.35 micrograms per liter (parts per billion) corresponds to a one-in-one-million excess cancer risk — the standard benchmark EPA uses for regulatory decision-making.
At 3.5 ppb, the excess cancer risk is one in one hundred thousand. At 35 ppb, one in ten thousand. These are not hypothetical concentrations. Groundwater near contaminated sites in New Jersey has been found to contain 1,4-dioxane at concentrations ranging from low ppb to hundreds of ppb. Some monitoring wells at active remediation sites have shown concentrations exceeding 1,000 ppb.
Where 1,4-dioxane comes from in New Jersey
TCA disposal sites. 1,1,1-trichloroethane was one of the most widely used industrial solvents from the 1950s through the 1990s — in manufacturing plants, machine shops, electronics facilities, dry cleaners, auto repair shops, and military installations. When TCA was disposed of, 1,4-dioxane was released with it. New Jersey has hundreds of sites with documented chlorinated solvent contamination, many of which have not been specifically tested for 1,4-dioxane.
Dry cleaning facilities. Many older dry cleaning facilities used TCA and other solvents containing 1,4-dioxane. New Jersey’s dense network of dry cleaning establishments — which operated for decades with minimal oversight — represents a significant distributed source of 1,4-dioxane contamination in urban and suburban groundwater.
Industrial manufacturing facilities. Pharmaceutical manufacturing, textile processing, adhesive manufacturing, and chemical production all used 1,4-dioxane as a processing solvent. New Jersey’s concentration of pharmaceutical manufacturing in the central and northern part of the state is particularly relevant.
Defense and military facilities. Military installations have historically used large quantities of TCA-based products for equipment maintenance. Former and active defense facilities in New Jersey have histories of chlorinated solvent contamination, and many have not been comprehensively assessed for 1,4-dioxane.
Industrial landfills. Legacy industrial landfills — many of them on or near the Superfund National Priorities List — accepted solvent-containing waste during decades when such disposal was standard practice. Not all of these sites have been tested for 1,4-dioxane.
The regulatory gap
New Jersey’s drinking water utilities are not currently required to test for 1,4-dioxane under the federal Safe Drinking Water Act. The EPA has not yet established a maximum contaminant level (MCL). Most New Jersey utilities have never tested for it, meaning residents have no way of knowing whether their water contains it.
The PFAS comparison: PFAS contamination followed a predictable arc — chemicals used industrially for decades, widespread groundwater contamination, no monitoring or regulation, alarming concentrations discovered in water supplies, and then a regulatory and legal response playing catch-up with a crisis that could have been mitigated by earlier action. 1,4-dioxane is at an earlier point on that same arc. The contamination exists. The sources are known. The health risks are documented. The regulation is absent. NJ Clean Stream is not willing to wait for 1,4-dioxane to become the next PFAS scandal.
Several states have acted independently. New York has established a 1 ppb MCL — the most stringent state standard in the country. Connecticut has established 3 ppb. California is developing its standard. New Jersey has the same authority and the same evidence. What it lacks is the political pressure from an informed public. That is what NJ Clean Stream is building.
What you can do right now
- Ask your water utility whether it has tested for 1,4-dioxane. There is no federal requirement to do so, but many utilities will respond to customer requests for voluntary testing. Ask specifically for results using EPA Method 522.
- Contact your state legislators. Ask whether they support establishing a New Jersey maximum contaminant level for 1,4-dioxane in drinking water. New York already has one at 1 ppb. New Jersey should too.
- Sign NJ Clean Stream’s petition for mandatory 1,4-dioxane monitoring at njcleanstream.org/take-action.
This is Article 1 of 3. Article 2 examines the specific industrial sites and geographic clusters of contamination in New Jersey, and the cost recovery framework. Article 3 explains why 1,4-dioxane is harder to treat than most contaminants and what regulators must do about it.