Concerned citizens can submit petitions asking the U.S Food and Drug Administration to take a closer look at certain food ingredients.
The Government Accountability Office calls these petitions "the most formal path for an individual or organization to bring a problem to the FDA's attention."
But some petitioners have been waiting for an answer for a decade or more.
Although the agency is required to offer some response within 180 days (usually a notification that it has reached no decision), there is no deadline by which the FDA must make a decision.
The Center for Science in the Public Interest has filed several petitions over the years, including those to modify the safety status of salt (2004) and revoke the safety status of trans fats (2005). They remain pending, to chagrin of the center's executive director, Michael Jacobson.
"FDA could snap its fingers and get trans fat out of the U.S. food supply by saying that it is no longer generally recognized as safe," he said. "There is enough science out there by independent researchers, the Institute of Medicine and American Heart Association to show that it is generally recognized as dangerous."
The GAO found in a 2010 report that "the FDA has largely not responded to the concerns that individuals and consumer groups have raised through 11 citizen petitions submitted to the agency between 2004 and 2008." To date the agency has answered only three of the 11 petitions — all denials.
Among the 11 is a 2006 petition on diacetyl, a buttery flavoring chemical that has been associated with lung disease in workers who handle it but, in 2007, was also linked to lung damage in a Colorado man fond of eating and smelling his hot butter-flavored microwave popcorn.
The FDA told the New York Times it would consider the Colorado man's case in its review of the chemical. Six years after the petition was filed, however, it remains unaddressed, and diacetyl is still classified by the FDA as "generally recognized as safe."
Although most microwave popcorn-makers have since voluntarily removed diacetyl from their products, several replaced it with 2,3-pentanedione, which this month was found by government researchers to pose similar respiratory dangers to workers as diacetyl. The study, by the National Institute of Occupational Safety and Health, part of the Centers for Disease Control and Prevention, did not examine possible effects of 2,3-pentanedione on consumers.
The risks with these chemicals were enough to prompt the CDC last year to recommend restricting workers' exposures to less than 5 parts per billion for diacetyl and 9.3 parts per billion for 2,3-pentanedione.