Maine’s Proposal for PFAS-contaminated Sludge: A Bad and a Worse Idea


Maine faces an alarming and growing public health problem as a result of sewage sludge laced with PFAS (per- and polyfluoroalkyl substances), that, when spread as fertilizer on Maine’s farmland, pollutes our food, farms, and groundwater with these toxic chemicals. The state has so far failed to address the problem—and now, it’s proposing a path forward that may be just as bad or worse.

At the August 28 PFAS taskforce meeting, Maine Department of Environmental Protection (DEP) Commissioner Jerry Reid suggested that the state continue to allow PFAS-contaminated sewage sludge to be spread on Maine farmland for a few more years before transitioning to burning that contaminated sludge.

This is a very bad idea.

Furthering Land Contamination

I have already written about the problems with the state’s current approach of allowing land application of contaminated sludge—which has the perverse outcome of essentially encouraging the contamination of clean land with toxic PFAS until it is too polluted to receive more.

The standards that DEP is using to determine “too polluted” are also likely ten times too high to protect health. (Read more about the issues with this approach in my recent blog post.)

At the taskforce meeting, several representatives from municipal wastewater districts, however, suggested that the current standards were too difficult to meet and should be raised even further, the health hazards we previously raised notwithstanding. What wasn’t discussed, however, was that industry has already successfully had the standards raised so that they are easier to pass.

When DEP first proposed the screening standards for PFAS in 2017, it proposed numbers far lower than were ultimately adopted. In response to substantial pushback from the wastewater and sludge industries, the agency increased the screening numbers, in some cases more than tenfold. The reasoning is somewhat complicated, but originally DEP had correctly assumed people would be exposed to PFAS from many sources, such as through food, consumer products, and household dust, in addition to drinking water potentially contaminated as the result of PFAS leaching out of land applied sludge.  Following the industry pushback, the standard was changed to allow sludge to pollute groundwater with PFAS to the point that using it for drinking water would put a person exactly at the maximum “safe” level —without any other sources of exposure.

Between relying on outdated toxicology that understates the health risks and modifying the risk modeling to meet industry concerns, the bottom line is that DEP is already allowing levels of PFAS in sludge and on fields that is too high.

When the agency eventually updates and lowers its screening numbers to reflect the rapidly growing scientific consensus of harm at lower amounts, it’s a safe bet that levels of PFAS in soil now considered “safe” will fall precipitously.

When that happens, the levels of contamination encouraged by DEP’s current policy may then actually necessitate expensive clean-up.

Incineration a bad (and unrealistic) option

It is also obvious that DEP is also not completely comfortable with its current policy that allows ongoing land application of sludge, with Commissioner Reid suggesting that he would like to move towards a solution that would actually eliminate the PFAS. DEP believes that incineration would do this. Unfortunately there is very little evidence this can actually work safely and consistently.  

In response to DEP’s interest in incinerating the PFAS-laden sludge, the Maine chapter of the Sierra Club offered the taskforce an impactful statement panning the proposal on behalf of the national organization’s toxics program. We agree strongly with their comments.

There is limited information available on the “thermal destruction” or incineration of PFAS, but what is known is troubling. The carbon-fluorine bond that defines the class is extremely strong and it requires very high temperatures to break down some PFAS, perhaps as high as 1050°C (nearly 2000°F). Once broken down, many highly toxic byproducts can be formed as the constituents cool back down, especially in the context of a complex mixture of other chemicals that could be found in typical sludge. 

While sludge is frequently burned in other states, these incinerators are not designed for the destruction of PFAS compounds. Neither these incinerators’ effectiveness at breaking PFAS down nor their production of toxic byproducts regulated or measured. Given that the entire goal of burning the sludge in Maine would be to address the PFAS contamination, it seems DEP needs assurance that PFAS would actually be addressed.

If there was even hope for PFAS to be incinerated in a way that could be effectively monitored, a more specialized hazardous waste incinerator would be required. However, as reported by Sharon Lerner in The Intercept, attempts to (ironically, perhaps) dispose of PFAS-based firefighting foam by incineration has raised more problems than solutions. In addition to great uncertainty and limited monitoring of toxic byproducts, many incinerators end up violating their permits and falling out of compliance with what is measured. Incinerating Maine’s PFAS-contaminated sludge will present similar concerns.

Incinerators are also known to exacerbate environmental injustice. Nationally, four out of five incinerators are located in low-income communities or communities of color. Many of these communities already face disproportionate risks for environmentally-linked illness. Building new incinerators, which will also likely end up in disadvantaged communities, or shipping more PFAS-laced waste to existing incinerators to further burden these communities, is not an equitable or acceptable solution to the problem.

Beyond the public health and environmental justice concerns, Commissioner Reid seemed to ignore the political reality in Maine when he suggested that an incineration option for the sludge would be plausible in a relatively short timeframe—just a few years. I beg to differ. It’s hard to believe that there would be a groundswell of support amongst the legislature or amongst Mainers already concerned about air pollution to accept new hazardous waste incineration facilities in state. This means that land application on farmland, the very thing DEP hopes to move away from with incineration, would have to continue substantially longer than DEP seems to want to believe.

Where from here?

Wastewater operators made clear to the taskforce that there are real challenges in how to manage the contaminated sludge, as has been highlighted in Presque Isle. These facilities have an understandable complaint that they were hit with this challenge with little notice and that it disrupted their plans and budgets.

We agree that the state must play a role in helping struggling community wastewater districts to address the fiscal challenges. But at the end of the day, these are professionally run, quasi-governmental entities who, when faced with complex challenges, have many resources to draw upon for solutions.

On the other hand, those potentially harmed by the ongoing land application of contaminated sludge or its incineration—farmers, children and families, and Maine communities—do not have these advantages. It’s incumbent on us all to address the challenge posed by PFAS-contaminated sludge in such a way that we aren’t creating more stories of devastation like Fred Stone’s.

That means no more spreading of contaminated sludge on fields. It also means not deploying scientifically suspect incineration methods.

Instead, we should focus first and foremost on eliminating the PFAS chemicals at their source so the sludge can be cleaned up. And in the meantime, it likely means landfilling sludge, which—while far from ideal—at least provides a location where it can be mostly controlled and monitored.