Farmers across Washington already spread thousands of tons of fertilizer from human waste on their crops each year, but there’s a major blind spot when it comes to potential contaminants.
Fertilizers made from human waste are fairly common across the country. Depending on who you ask, they’re called “biosolids” or “sludge,” and they can be seen as a frontier of the agricultural world or a health hazard. Increasingly the industry has a new specter: the slate of toxic chemicals known as per- and polyfluoroalkyl substances, or PFAS, which cause cancer and a host of other health problems. Contamination is so bad in some places that Connecticut and Maine have banned the use of biosolids on agricultural lands.
In Washington — particularly King and Pierce counties — experts say the PFAS problem isn’t nearly as pronounced. The contaminants are likely present, they’re even detectable in rain water across the world, but probably not in such high concentrations as to be dangerous, they say.
But here’s the thing: We don’t know for sure.
A new bill under consideration at the statehouse would look to change all that.
Waste treatment plants that turn human waste into fertilizer or compost aren’t required to test for these forever chemicals. And even if waste plants do test, there’s no specific limit for the compounds.
The bill’s sponsor, state Sen. Jeff Wilson, R-Longview, told the chamber’s Environment, Energy and Technology Committee last week that his bill is a way of protecting both human health and the ability to use these fertilizers.
“Biosolids: they’re good,” Wilson said. “But biosolids with question-mark levels of forever chemicals may not be good.”
If passed, the bill would require the state Department of Ecology to establish PFAS sampling and testing requirements for biosolids by July 2027. A year later, the department would be required to finish an analysis of PFAS levels in biosolids produced in Washington, and by the end of 2028 it would have to report its analysis back to the Legislature with recommendations on how to move forward.
This is the third time a bill like this has been introduced at the statehouse, but this year Wilson said it might make it all the way to the governor’s desk. PFAS contamination from biosolids use has made national headlines in recent months, with the U.S. Environmental Protection Agency warning that these compounds found in sewage can exceed safety limits several times over.
Increased testing really isn’t a controversial topic, either. King County has already conducted a single, yearlong analysis of its own product, called Loop, though results aren’t yet available. Spokesperson Akiko Oda said the county supports Wilson’s bill and ongoing testing requirements. Already, they routinely test for pathogens, heavy metals and trace chemicals and are developing plans for ongoing PFAS monitoring and testing, she said.
Human waste streams don’t create PFAS. The compounds flow into treatment plants through the products we use and ingest or from upstream sources like industrial manufacturers or stormwater flows. An uptick of forever chemicals could be managed by seeking out the upstream source and stanching the flow there. Oda said King County is continuing its efforts to control those sources and holding producers responsible for the cleanup costs.
Last week more than a dozen people testified before the committee, generally supportive of the measure. Some expressed concern that the bill doesn’t go far enough, asking instead that legislators ban the use of biosolids for agricultural purposes entirely. Aside from PFAS contamination, others expressed concerns about pathogens that can be spread through human waste and the development of antibiotic-resistant bacteria.
State law requires treatment plants to find a “beneficial use” for waste before they can consider incinerating or landfilling it. This bill would help Washington understand if its biosolids programs have a PFAS problem and, if so, how bad it is, Wilson said.
“Let’s not scare ourselves to death, but certainly no more turning a blind eye to something that has a forever impact on our bodies,” Wilson said.
The bill is scheduled for a vote in the Senate committee Tuesday afternoon.
