Investigations into spikes of 1,4-Dioxane in Asheboro, High Point still inconclusive
High levels of toxic chemical also being legally released from DAK Americas in Fayetteville, prompting review of facility’s permit
This map shows where DEQ has issued permits with some requirements or restrictions on discharge of 1,4-Dioxane. There is no legally enforceable standard for the toxic compound, but DEQ has set health goal of 0.35 parts per billion in drinking water supplies.
Until 1989, when the company declared bankruptcy, Seaboard Chemical Corporation in Jamestown, in Guilford County, dealt in the dirty business of solvents and fuels. Now the fallow property on Riverdale Drive lies behind a locked gate and a thicket of pine trees, what some local residents called the “1,4-Dioxane forest.”
The groundwater beneath the former Seaboard site is highly contaminated with 1,4-Dioxane, a known carcinogen. Though not as well known as PFAS, 1,4-Dioxane is likewise what federal regulators call an “emerging compound” — relatively unknown chemicals that are being detected more often and more widely, in the air, dirt and drinking water supplies. While in a different chemical family than PFAS, 1,4-Dioxane shares another characteristic besides toxicity: It’s a forever chemical that lingers in the environment for decades, if not hundreds of years.
Neither the EPA nor the NC Department of Environmental Quality have established legally enforceable limits on 1,4-Dioxane, even though it’s a known carcinogen. State regulators have established an unenforceable health advisory goal of 0.35 parts per billion in drinking water supplies.
As part of a settlement agreement with the Haw River Assembly, DEQ provides updates on 1,4-Dioxane — discharges, spikes, monitoring and other data — twice a year to the Environmental Management Commission. Hovering over the agency’s latest presentation last week was House Bill 600. If it becomes law as written, DEQ couldn’t limit the amount of 1,4-Dioxane and other toxic chemical discharges unless they can be measured by a number. That would require rulemaking by the EMC.
(The EMC did just that, last year, setting a target based on the existing goals set by DEQ. But the Rules Review Commission nullified the EMC’s action, concluding its fiscal analysis was insufficient and needed to be redone.)
1,4-Dioxane enters the drinking water when industry discharges the compound in its wastewater into municipal treatment plants. Since traditional treatment technologies can’t remove 1,4-Dioxane, it persists in the plants’ wastewater that in turn enters rivers, lakes and streams.
From there, it can contaminate the drinking water. Pittsboro, for example, has borne the brunt of 1,4-Dioxane contamination in the Upper Cape Fear River Basin. The town sources its drinking water from the Haw River in the Upper Cape Fear River Basin, which has been polluted by cities and industries upstream.
In 2021, DEQ sampled surface water in 28 places within the Cape Fear River Basin. Of the 262 results, a third — 81 — had some level of 1,4-Dioxane.
To get a fuller understanding of the extent of 1,4-Dioxane contamination, DEQ is requiring 18 facilities, such as wastewater treatment plants and industrial facilities to monitor for the compound; another five permits are pending or being reassessed, according to a presentation last week to the EMC. (Scroll down to see the full list.)
A few facilities have permit limits on the amount of 1,4-Dioxane they can discharge into waterways.
“We want to protect people, but what if we have too much margin of error?” asked EMC member J.D. Solomon of an agency official about permit limits. Solomon, an appointee of House Speaker Tim Moore, often advocates for less stringent regulations.
“I’d say we don’t [have too much margin of error], replied Julie Grzyb, deputy director of the Division of Water Resources. “It’s a water supply so the discharge should meet the standard of a water supply.”
High Point’s East Side wastewater treatment plant is across Riverdale Drive from the old Seaboard site. While Seaboard has leached 1,4-Dioxane through the groundwater into Randleman Lake, the drinking water supply for Greensboro and many Guilford County municipalities, the connection between the old chemical plant and the High Point wastewater treatment plant is less clear.
What state regulators do know is that High Point, as well Asheboro, are struggling to rein in their 1,4-Dioxane discharges. Meanwhile two other cities – Greensboro and Reidsville – have finally curbed their 1,4-Dioxane loads into the Upper Cape Fear River Basin, according to the EMC presentation.
Farther downstream, DAK Americas, a chemical manufacturing plant in Fayetteville that sends its wastewater into the Lower Cape Fear River, chronically violates its permit limits on 1,4-Dioxane.
Companies that manufacture plastic and polyester resins, such as DAK Americas and Starpet, often produce the compound as a manufacturing byproduct. Other processes use 1,4-Dioxane as a solvent and degreaser. The compound is present in some cosmetics, shampoos, paints, dyes, adhesives and cleaning products. 1,4-Dioxane, like PFAS, is seemingly everywhere.
High Point: Multiple industrial suspects
In May of this year, as part of its monitoring requirements, the City of High Point notified state regulators that 1,4-Dioxane levels leaving the East Side plant had reached 681 parts per billion. Subsequent testing by DEQ showed concentrations approaching 1,000 ppb.
DEQ representatives debriefed EMC members on an investigation into the source. High Point officials contacted Innospec, which provides chemicals, additives, and formulations for a variety of industries. Company officials said they didn’t make 1,4-Dioxane, but agreed to send samples for analysis. Innospec then notified the city that it had technical and personnel issues that prevented the company from collecting samples on time. The samples Innospec did provide four days late “were inconclusive and did not directly implicate them,” according to DEQ.
Alberdingk Boley, which makes resins and adhesives at its Greensboro plant, did make 1,4-Dioxane that week. However, company officials said the chemical is eliminated as part of a manufacturing process, also known as a “boil out.”
“But that wasn’t true,” Jenny Graznak, assistant regional supervisor for DEQ’s Winston-Salem office, told the EMC. “Nonetheless, they couldn’t have been solely responsible for that magnitude; but they could have contributed. The industry manufactures these products sporadically. These are not products they’re making 24-7. It’s not a steady flow.”
High Point officials continue to sample other areas throughout the wastewater collection system.
Asheboro: Landfill could be a source
Asheboro’s spikes could be originating from landfill leachate — liquid that accumulates in a landfill’s collection system. The leachate is sent to the Asheboro wastewater treatment plant, which discharges into Haskett’s Creek, a tributary of the Deep River. The City of Sanford taps into the Deep River for its drinking water.
The leachate could explain the peaks, Graznak said. “What they’re getting from the landfill, it’s a slug, and it happens at random, whenever the lift station at the landfill operates.”
Since 1,4-Dioxane is found in many consumer products that are thrown away, leachate can also contain the compound as those products break down or as rain enters the landfill. A 2019 study commissioned by DEQ found that leachate is a minor contributor to a wastewater treatment plant’s overall 1,4-Dioxane load.
There is one industry in Asheboro that uses or produces 1,4-Dioxane, Starpet, which makes plastic bottles. However, Graznak said, Starpet has a special treatment system to reduce the amount of the compound in its discharge.
DAK Americas: Another reason to reduce plastics
Dak Americas, an international plastics manufacturer, discharges its wastewater into the Cape Fear River. It is a known source of 1,4-Dioxane.
As NC Newsline previously reported, DAK Americas shipped sludge from its wastewater treatment plant to McGill Environmental, a compost facility in rural Sampson County. The sludge contained levels of the compound at more than 20,000 ppb. (Because the compound evaporated as the compost dried, it was not detected in the finished product. However, the compost did contain PFAS, which had several sources, including DAK.)
DEQ has placed limits on DAK’s discharge of 1,4-Dioxane, but the facility consistently exceeds the maximum. “DAK’s limit is substantial but their effluent also substantial,” said Michael Montebello, chief of the discharge permitting program branch. The agency has not penalized the company for these exceedances. However, it is reconsidering DAK’s permit limits based on public comments, Montebello said, and could set a timeline for the company to comply.
In two cities, lawsuits, fines, and cracking down on industry got results
It took four years, but Reidsville has managed to curtail its 1,4-Dioxane levels. In 2019, DEQ sampling showed concentrations reached 1,400 ppb; this year the peak has been 10 ppb and as low as 1 ppb, state data show. DyStar and Unifi were previously identified as potential sources of the compound. Industry users in Reidsville have either reduced or replaced their use of the compound.
Greensboro is in its third and final year of a Special Order by Consent with the state. That order and a subsequent legal settlement with the Haw River Assembly require the city’s T.Z. Osborne wastewater treatment plant to reduce 1,4-Dioxane in its discharge to just 23 parts per billion. (While this is higher than the health advisory goal, the limit was set based in part on dilution in the waterways.)
The city has succeeded, according to a DEQ presentation to the Environmental Management Commission. In 2021 1,4-Dioxane levels leaving the Osborne plant spiked at more than 900 ppb. In the first four months of 2023, the highest concentration was roughly 5 ppb.
Greensboro achieved this by extensive sampling and cracking down on industries that use or produce 1,4-Dioxane.
Shamrock Environmental, which transports industrial waste, and Lanxess, a chemical company, were identified as industrial sources of the compound.
Lanxess discontinued using 1,4-Dioxane and replaced it with another chemical. Last year the company was purchased by Hallstar, which is also prohibited from making the compound.
“It’s encouraging that the source of the spikes would be identified and addressed without major treatment costs” on the wastewater treatment plants, said EMC chairwoman Robin Smith. “There are other ways to eliminate the sources.”
Facilities with discharge permits for 1,4-Dioxane
|Nokia of America||Winston-Salem|
|Stepan Company (Invista)||Wilmington|
|Radiator Specialty||Indian Trail|
|Tar River Regional WWTP||Rocky Mount|
|Moncure Holdings West||New Hill|
|Siler City WWTP||Siler City|
|Rockfish Creek WRF||Fayetteville|
|South Durham WRF||Chapel Hill|
|Dutchman Creek WWTP||Mocksville|
|Big Buffalo WWTP||Sanford|
|Holly Springs WWTP||Holly Springs|
|Press Club Cleaners||Charlotte|
| Colonial Pipeline
Facilities whose discharge permits for 1,4-Dioxane are pending
or being reassessed*
|Western Wake Regional WWTF||New Hill|
|North Harnett Regional WWTP||Lillington|
|Charlotte McAlpine WWTF||Pineville|
|*Dak Americas, Cedar Creek||Fayetteville|
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