Thanksgiving is the holiday most associated with celebrating healthy and abundant food. For many, it is also be a time when we recommit ourselves to creating an organic food future that promotes, safe, local, humane, socially just and biodiverse food production.

An under-publicized and often hidden threat to this food future is the increasing use of sewage sludge as fertilizer for our food. Of course, no one wants their sweet potatoes grown in this sludge or their turkeys feeding on sewage-contaminated food. In fact, sludge is a prohibited method under our national organic rule and even some major food companies won't use it, but that hasn't stopped our local, state and federal governments from secretly foisting it on us.

Sludge, for those to whom this is new, is that toxic mix that is created by our municipal wastewater treatment facilities. Just about anything that is flushed down toilets or that ends up in sewers is in this sludge; the pollutants in sludge come not just from household sewage, but also from every hospital, industrial plant, and stormwater drain. Note that our federal government has prosily and misleadingly renamed sludge "biosolids"; don't be fooled. It's just the same old sludge with a PR spin.

So how did sludge get on our farm land? Well, for a long time we simply dumped sludge in the oceans. Over time, it became apparent that this was an environmental and human health disaster. An alternative solution has been pushed since the 1980s by the U.S. government. The EPA determined that a good way to dispose of treated sewage sludge was to legally distribute it as a cheap alternative to fertilizer. That's right: it's unsafe to have in the oceans, but we're encouraged to grow our food in it. Unsurprisingly, scientific analysis of the poisons in sewage sludge shows it's the wrong, and dangerous, solution for U.S. farmers and communities.

Unfortunately, many American farmers and gardeners are unknowingly using sludge-derived "compost." One reason for this is that sludged compost is being given away free in many cities throughout the United States, and as a result, farms and homes across the country have been unknowingly spreading hazardous chemicals and heavy metals on their fields, lawns and gardens. The problem has affected even our most prestigious residence--the White House. First Lady Michelle Obama herself has taken commendable steps to alleviate contamination from sludge-based fertilizer in her garden, a result of sludge used on the White House lawn more than a decade ago.

Courts have also weighed in on the dangers of sludge and the failure of the EPA to protect our food and farms. A federal court in Georgia recently ruled that land application of sewage sludge was the cause of contamination of several farms and the cause of death of the plaintiff farm's prizewinning cattle. The court also found that rat poison in sludge came out in milk distributed via commerce. It also turns out that in defending its sludge program in this case, the EPA used fraudulent data and tried to hide what they were doing. As the court noted: "The administrative record contains evidence that senior EPA officials took extraordinary steps to quash scientific dissent, and any questioning of the EPA's biosolids program."

Despite this case and mounting evidence of the dangers in biosolids, sludge giveaway programs continue unabated and are often accellerated. Even the "green "city of he San Francisco has a sludged compost distribution program run by their Public Utilities Commission (SFPUC). The SFPUC does outreach to organic gardeners and homeowners alike urging them to use the material as fertilizer on vegetable gardens, lawns, farmland, flowerbeds, and - in particular - on schoolyards and playgrounds.

Misleadingly, the City calls this a compost giveaway when it is really a sludge giveaway. The City has even called this sludge "organic" compost. . The SFPUC should know that, as I've already mentioned, sewage sludge is a "prohibited method" under the national organic regulations so it is not only misleading but potentially illegal for the city to label sludge-derived compost as "organic."

There is very good reason to prohibit growing organic food in sewage sludge. While the natural elements in compost break down in soil, sewage sludge contains heavy metals and myriad chemical pollutants that remain in the soil for years. Neither treatment nor composting removes the material's toxins and heavy metals which persist in the soil and which may contaminate the foods grown in it. For these reasons, using sewage-sludge-based fertilizer on playgrounds and school gardens is particularly egregious when you consider the potential for children's exposure to these highly toxic substances.

San Francisco's should know better. Its sludge tested in 2008 included poisons like p-Isopropyltoluene, an industrial chemical used to manufacture consumer goods; 1,4-Dichlorobenzene, a disinfectant and pesticide; tolulene, an aromatic hydrocarbon used as an industrial solvent; 1,2,4-Trimethylbenzene, a product of petroleum refinery distillation; and phenol, also known as carbolic acid, used in the manufacture of drugs, antiseptics, and the manufacture of synthetic fibers. What's worse, the sludge-derived "compost" they are pushing comes from numerous other counties in California whose sludge had not been tested at all. This grossly violates the precautionary principle that San Francisco has officially adopted as its rule of thumb for its government programs.

Put simply, under the guise of a simple "recycling solution," the City is poisoning its residents' backyards, schoolyards, and gardens. And the people of the Bay Area are not the only ones at risk. Similar giveaways of fertilizer made of sewage sludge are occurring in cities like Austin, Texas and Eureka, California. Most of these cities have a reputation for progressive, green practices, but participation in these polluting programs puts those reputations at serious risk.

So, this year, give thanks for your food, but not for the toxic sludge that's been given to you as compost. We understand the need to dispose of sewage sludge, but moving it onto soil and into food production is not the answer. This practice, while convenient and profitable for a few companies, violates the duty of government to protect the health and welfare of its citizens. Source separation, reduction, and--where the wastes are too hazardous to reuse--containment, are the elements of a safe recycling plan. It's long past due that the EPA, the wastewater treatment industry, and city governments acknowledge the truth about sewage sludge distributed as fertilizer: it's not safe, it's not compost, it's not organic, and it's certainly not cheap. Indeed, our communities and children could pay a steep human health price.