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.