Although the current flashpoint is San Francisco, municipalities across the country are looking for places to put their sludge. The CFS has an on-going, nationwide program to shine light on the environmentally questionable practice, and the Organic Consumers Association, an advocacy group, announced last month that it is about to launch a "major campaign against the sewage sludge industry."

In September the CFS, joined by the Resource Institute for Low Entropy Systems, (RILES) a Boston-based organization that works to protect public health and the environment, petitioned the city to stop the giveaways. "We're not telling San Francisco what to do with their sewage sludge. We're just asking them to stop the program because of all the unknowns and because of the potential for it to be misleading and deceptive," Paige Tomaselli, the staff attorney in the CFS's West Coast office, said in an interview. "Residents could be at serious risk of poisoning from the application of sludge to crops and gardens."

In late November the groups got an answer to their petition. Speaking before a citizens' advisory committee, Natalie Sierra of the public utilities commission, said that, far from ending the program, the city hoped to expand it ten-fold.

At that point the sludge really hit the fan.

"San Franciscans are getting the wool pulled over their eyes," said Laura Orlando, the executive director of RILES, in an interview. "It is a toxic product. The citizens of San Francisco don't know what they are getting. They think they are getting free compost from the city. They don't know they are putting sewage sludge on their lawns, and people don't want to eat food grown in sewage sludge."

Orlando notes that advertisements put out by the city fail to identify the compost as being based on sludge, instead relying on the term, "biosolids," a euphemism coined in the 1970s by waste water managers looking for a sanitized word for, well, shit. Also misleading, according to Orlando, is the term "organic," used by the city to describe its compost. "Food that receives USDA organic certification cannot be grown with sludge," she said.

Phone calls to the Public Utilities Commission were not returned, but in a statement, spokesman Tony Winnicker said, "San Francisco's biosolids compost is safe, tested, and great for plants. It is tested for metals and other contaminants and meets or exceeds all standards," almost making it sound like the eco-friendly flipside of the locavore movement.

Tomaselli of the CFS does not dispute Winnicker's claim that San Francisco's sludge might be "greener" than sewage solids from more industrialized and less environmentally enlightened cities, nor does she argue that it fails to meet standards set by the Environmental Protection Agency (EPA). But, pointing to a 2008 court case where a federal judge ruled in favor of farmers who sued the United States Department of Agriculture (USDA) when their cows became ill and died after eating silage grown on land upon which sludge had been applied, she noted that the city was abiding by the "same rules that sickened those cows."