SNOQUALMIE, Wash.—Out in the Snoqualmie forests of eastern King County, on the west side of the Cascades, the ground is black and mucky. It's an unnatural scene with a toilet-bowl stench.

And it comes from tons upon tons— about 120,000 tons a year—of sewage sludge that King County, home of Seattle and more than 2 million people, disposes of annually in these forests and on farms and rangelands of central and eastern Washington.

This sludge, known euphemistically as "biosolids," consists of semi-liquid waste obtained from the processing of municipal sewage. The goal of this process is to obtain clean water to release into the environment, and thus, the cleaner the water, the more toxins and contaminants are retained in the sludge. This sludge used to be dumped into the ocean, but because of its toxicity this process is banned. Instead we now spread it in our forests and on our agricultural lands.

The spreading of this sludge carries considerable risk and should be stopped. As scientists, we are increasingly concerned with this reckless practice.

One of the biggest anaerobic digesters in the region is scheduled to be built on Long Island, the state announced today.

The digester, essentially a giant set of eight tanks hooked up by pipes to a 90,000 square foot warehouse, will be capable of converting roughly 160,000 tons of organic waste into natural gas, diverting the waste material from landfills.

“This first-of-its kind project for Long Island and the greater New York metropolitan area will build upon this administration’s commitment to expand the state’s use of renewable energy and reduce our carbon footprint," Gov. Andrew Cuomo said in a statement.

The city's actions are a wake-up call that the entire nation regularly consumes foods grown on fields fertilized with sludge.