Sludge containing 1,4-Dioxane was used
to make compost and fill,
destined for gardens, farms and parks.
Because of weak EPA and state rules,
it’s completely legal.

 

Investigation shows that dangerous chemical was included in materials received by NC composting facility

This is the first of a two-part investigation into how the lack of federal regulations and state oversight allowed 1,4-Dioxane, a likely carcinogen and emerging contaminant, to be trucked in wastewater sludge to a North Carolina compost facility. Part 2 runs tomorrow morning. 

2,300 words, 12-minute read

Dusky and speckled with bits of turquoise and green plastic the size of a sesame seed, the sludge smelled rank. It was a common odor for wastewater residuals, the worker noted, but the material also emitted a strange scent, like solvent, which seemed ill-suited for compost.

On this mid-winter’s day, nearly seven tons of the residuals — less elegantly known as sludge — were trucked from DAK Americas, an international plastics manufacturer with a plant in Fayetteville, 40 miles to McGill Environmental, in rural Sampson County. There, the sludge would be combined with other detritus: peanut shells, poultry manure, hog waste, sheet rock, wood and treated sewage sludge. Eventually the material would be turned into compost, soil builder or fill, destined for gardens and farms, roads, parks and playgrounds.

The worker’s hunch was right. A four-month Policy Watch investigation found very high concentrations of a toxic substance in that day’s shipment from DAK to McGill: 1,4-Dioxane. An industrial chemical that the EPA has linked to cancer, it was present in the waste at a concentration of 20,400 parts per billion, higher than levels the EPA has found at some hazardous waste landfills. Even at this level, however, the presence of 1,4-Dioxane is legal. Despite the compound’s known threats to human health and the environment, it is unregulated. Instead, the EPA calls it an “emerging contaminant of concern,” whose risks, like perfluorinated compounds (PFAS), merit further study.

Policy Watch’s findings also reveal a loophole in state regulations, one that allows compost operators and the suppliers of raw materials to operate on a tenuous honor system: Composters don’t have to test for 1,4-Dioxane or any emerging contaminants. And industrial plants don’t have disclose to the composters if those compounds are present in the material they’re sending.

Policy Watch obtained two quarts of sludge from a seven-ton load and took it to Pace Analytical, an EPA-certified lab, the same day. About 10 days later, after conferring with the lab, Policy Watch informed both companies and the state Department of Environmental Quality of the results. DAK halted its shipments to McGill for one week, according to the worker, who was familiar with the transportation schedule. 

It’s uncertain if the test results prompted the hiatus. DAK did not respond to repeated requests for an interview. Neither McGill President Noel Lyons nor Vice President Steve Cockman responded to requests for an interview. Gary Gittere, sales and marketing manager for McGill and board president of the NC Composting Council, referred questions to the US Composting Council.

Policy Watch agreed not to name the worker who provided the tip because they were afraid of losing their job.

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The Division of Water Resources did intervene, and “has been in contact with DAK Americas,” said DEQ spokeswoman Laura Leonard, about assessing the levels of 1,4-Dioxane throughout the Cape Fear River Basin and working on ways to reduce those levels. Two samples of McGill finished compost were sampled on April 10; preliminary results are expected by the end of the month.

Several weeks after testing the sludge, Policy Watch took McGill compost to the same Pace lab for analysis. No 1,4-Dioxane was detected. However, the compost could have been processed after the companies became aware of the test results. Or it could have been made from a different batch of “feedstock” — industry parlance for material entering a compost facility.

McGill is ultimately responsible for the feedstock that enters its facility, but the rules are loose.

“DAK and McGill work out who is responsible for sampling as long as one or the other samples the raw material,” Leonard said.

Regardless of the EPA’s regulatory inertia on 1,4-Dioxane and PFAS, North Carolina has an opportunity to strengthen its own regulations. But so far, the draft compost rules, up for readoption by the Environmental Management Commission this year, require no testing for emerging contaminants. They ignore the possibility that these compounds could taint compost.

“We need a tracking system for industrial inputs into beneficial use and compost,” said EMC member Albert Rubin. A professor emeritus at NC State University, Rubin is an expert in wastewater management. “I believe strongly in beneficial use, but not contaminated beneficial use.”

 

Scientists know 1,4-Dioxane can cause cancer. Rats exposed to high levels of the compound in water and air developed tumors of the nasal cavity and liver. Even at lower doses, human studies show that when inhaled, the compound can irritate the nose, eyes, throat and lungs. Long-term exposure can damage the kidneys, liver and nervous system.

Workers, like those at DAK and McGill, can be exposed to 1,4-Dioxane by inhaling its vapors or touching it. The general public comes into contact with the compound through residue in medicines, household cleansers, lotions and shampoos, and by drinking contaminated water.

1,4-Dioxane loves water. It also loves to travel, often far from its source.

The compound can enter waterways through direct discharge into a river. It might infiltrate the groundwater from industrial leaks and spills that have drained through the soil. It can run off land where contaminated sludge or even compost have been applied.

Once it enters the water, 1,4-Dioxane dissolves. It hitchhikes downstream or through fractures in underground rock. From there, it can enter public water systems or private wells, contaminating drinking water far from the original pollution source.

Rebecca Sadosky, who coordinates DEQ’s Drinking Water Protection Program, told a national gathering of drinking water administrators last year that more than 1,000 public drinking water supplies in 45 states, including North Carolina, contain some level of the compound.

In North Carolina, the 1,4-Dioxane hotspots lie in the Cape Fear River Basin, which reported four of the highest surface water detections nationwide. Yet the source of 1,4-Dioxane is not a mystery. Industrial plants, including DAK, discharge it directly into the Haw, Deep and Cape Fear rivers. Contaminated lakes and rivers lead to polluted drinking water. In the past four years, Fayetteville, Pittsboro and Wilmington, all in the Cape Fear River Basin, have reported concentrations in drinking water above the EPA’s voluntary health advisory goal of 0.35 parts per billion.

North Carolina has also adopted the EPA drinking water goal as well as the federal agency’s goal of 3 ppb for groundwater. Absent EPA guidance, other states have set their own regulatory standards and guidelines.

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Industry can also send its contaminated wastewater to cities’ wastewater treatment plants, which are unable to remove 1,4-dioxane. In a seemingly unbreakable feedback loop, the cities discharge contaminated wastewater back to the rivers — the drinking water supply.

Industrial plants might also ship their contaminated sludge to city landfills or to composting facilities, like McGill, where the material might taint the finished product and the sites to which it is applied. If compost or fill contained high levels of 1,4-Dioxane, it would likely leach into groundwater or surface water, said Detlef Knappe, an NC State University professor and scientist, who co-discovered the extent of 1,4-Dioxane and PFAS in the Cape Fear River Basin.

“I think key steps would be to understand where the 1,4-Dioxane is coming from and to identify an effective treatment strategy so that 1,4-Dioxane is eliminated from the wastewater and the sludge,” Knappe said. “Material containing emerging contaminants of concern should not be used in compost.”

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Situated in the heart of hog country in Sampson County, McGill Environmental sits about 50 yards off Herring Road, behind a chain link fence and obscured by trees. New Hope and Clear Run creeks flank the facility, which, satellite imagery shows, includes a field of dark brown material that resembles a giant chocolate brownie.

Because of its size and the numerous types of materials it can accept, McGill is classified as a Type 4 composting facility. Smaller enterprises — designated by the state as Types 1 through 3 — are limited on the types of feedstock they can accept, as well as the amount of compost they can produce each year.

Most of North Carolina’s 70 composting facilities are Type 1 or 3, according to a DEQ database. Of the three privately owned Type 4 facilities, two belong to McGill, in Sampson and Chatham counties (see map below).

When DAK sludge arrives at McGill, it is offloaded into an enormous pit, where it is mixed with other feedstocks also classified as non-hazardous: chicken litter, hog waste, food scraps, yard clippings, animal bedding, pharmaceutical residuals, biodegradable plastic and wood chips. The material is then piled, aerated, regularly turned, and heated to a minimum of 140 degrees for several weeks to kill pathogens.

State rules require compost companies to test their finished product — but not feedstock — once every six months or every 20,000 tons, whichever comes first, or if they have begun accepting new types of material. The company must sample finished compost twice per year for hazardous waste and monthly for metals and pathogens.

Yet federal and state rules mandate that compost companies test for only a small number of contaminants: bacteria and viruses, plus eight metals, such as arsenic, copper and lead. No tests are conducted to detect PFAS or 1,4-Dioxane. 

From 2015 to 2017, McGill produced more than 38,550 tons of compost and fill, according to the company’s annual reports filed with DEQ. That material was destined for farms, garden and landscaping businesses, and even city parks and recreation departments for use in playgrounds and soccer fields. During that time, McGill accepted 1,465 tons of waste from DAK plants in the Southeast: Leland in Brunswick County, which has since closed and is being overseen by the state’s hazardous waste branch, Fayetteville, as well as Columbia, and Cooper River in South Carolina. All of those DAK plants generate 1,4-Dioxane and emit it into the air, according the EPA’s Toxic Release Inventory. Three of the facilities, including Fayetteville, discharge the compound into nearby surface waters.

(Over those three years, McGill also accepted a smaller amount of feedstock, 121 tons, from Invista, a plastics company in New Hanover County; it also produces 1,4-Dioxane from its manufacturing process, according to the EPA.)

Until recently, the compost industry was concerned with measuring only a limited set of potential contaminants in its product: pathogens that can make people sick, metals that can contaminate crops or accumulate in the soil and leach into groundwater, and nitrogen and phosphorus that are beneficial for agriculture, but that can, in excess, overload the fields or run into waterways, where they contribute to the development of harmful algal blooms.

Now, with greater scientific awareness and scrutiny of PFAS and other emerging contaminants, the compost industry is also concerned about the integrity of its products. Since the composting process does not eliminate 1,4-Dioxane or PFAS, the industries supplying the feedstock should ensure it’s not contaminated before offloading the material, said Linda Norris-Waldt, spokeswoman for the US Composting Council, a national trade group based in Raleigh.

She told Policy Watch that PFAS have been detected in compost and similar products during their manufacturing. “It is the responsibility of the EPA to trace the sources of these materials to the manufacturer,” Norris-Waldt said. “The EPA should require all products that contain PFAS to be removed from production and sale.”

It is possible, although not verified, that some of the feedstock entering McGill also contained PFAS from the Cape Fear River Basin. State records show that from 2015 to 2017, McGill accepted sludge from several municipal treatment plants in the basin, including Bladen Bluffs, the Town of Cary and Brunswick County.

Since 1,4-Dioxane has been found throughout the Cape Fear River and its tributaries, it’s possible the utilities’ sludge contained the compound, as well. Conventional wastewater treatment can’t remove PFAS, GenX or 1,4-Dioxane.

In 2017, effluent from DAK’s own wastewater treatment plant contained nine types of PFAS, including PFOA and GenX, which were discharged into the Cape Fear River, state records show. Since the monitoring was limited to PFAS, it could not have detected (and the results did not include readings for) 1,4-Dioxane.

The US Composting Council recommends that consumers buy compost or compostable materials that have been certified by the Biodegradable Products Institute. As of March 31, all companies seeking BPI certification must have submitted tests verifying that the products contain no more than 100 parts per million of fluorine, which is present in PFAS.

“BPI has moved to not certify any compostable products that contain PFAS,” Norris-Waldt said. “I cannot speak to 1,4-Dioxane.”

Without testing previous loads of DAK sludge it’s unknown if additional shipments were contaminated with 1,4-Dioxane. And there have been a lot of shipments: According to McGill’s annual reports filed with DEQ, from 2015 to 2017, the facility accepted shipments of sludge from DAK plastics plants in North and South Carolina on an almost monthly basis.

DEQ prohibits McGill from accepting hazardous material. On its website, McGill says it reviews incoming feedstock “prior to contract and acceptance” to comply with EPA, state and company standards for finished compost, and that “additional testing may be required, depending on the material to be processed.” Since the EPA doesn’t classify 1,4-Dioxane as hazardous, except under limited circumstances, these standards don’t include the compound. Nor do they encompass the thousands of types of PFAS.

But improper material has slipped through McGill before. DEQ cited the company in 2008 for accepting sludge from Lakewood Trucking. The waste was deemed hazardous not for its chemicals but for its ignitability: It had a “flash point” — a temperature at which its vapors could ignite — of 114 degrees. Since compost piles get hotter than that during processing, the material could have caught fire.

A follow up inspection showed the company had fixed the problem. A DEQ inspector wrote at the time: “McGill has restructured the way they accept material into their facility to ensure they are not taking in unacceptable material.”

Tomorrow: DAK Americas is a source of 1,4-Dioxane. But our addiction to plastics is also in part responsible for the compound’s proliferation. Plus, learn how to ensure your compost is safe and how to comment on the state’s readoption of compost rules.