Back in May, I drew attention to the remarkable fact that food-industry workers are literally dying from exposure to a key ingredient in microwave popcorn.

The food additive diacetyl (responsible for that "buttery note" in nuked popcorn and also in margarine) emits a noxious fume when heated up — one that can literally destroy people’s lungs in high concentrations. Exposure to diacetyl has been decisively linked to a condition known with chilling accuracy as "bronchiolitis obliterans" — an irreversible lung disease usually found only in survivors of serious fires.

In that post, I wondered whether consumers of microwave popcorn — as well as home cooks who sauté with margarine — might be exposing themselves to serious lung damage, too. Turns out, they may well be — and federal agencies don’t seem to give an unpopped corn kernel about it.

Over on the excellent public-health blog The Pump Handle, David Michaels, a professor at George Washington University, head of the Project on Scientific Knowledge and Public Policy, and a former Clinton Administration public-health official to boot, points to a recent case of bronchiolitis obliterans found in a patient who ate microwave popcorn daily.

The patient’s doctor, Cecile Rose of the prestigious National Jewish Medical and Research Center in Colorado, issued a blunt letter describing the case, dated July 18, to all the big national public-health agencies — the CDC, FDA, OSHA, EPA. Their response, according to Michaels: dead silence.

Concludes Michaels:

It appears that the Bush Administration’s efforts to destroy the regulatory system are succeeding; the agencies seem unable to mount a response to information that a well-functioning regulatory system would immediately pursue. The agencies aren’t even trying to connect the dots.

Meanwhile, Liz Borkowski, a colleague of Michaels’ at the Project on Scientific Knowledge and Public Policy, tells me that the group has tried to get the EPA to release results of its study on popcorn-related diacetyl emissions, even issuing a Freedom of Information Act (FOIA) request.

The result? Dithering. "They did send us a lot of documents in response to our FOIA request, but classified the study itself as a nonreleasable record," Borkowski wrote me in an email.

While the EPA cravenly hides the study from the public, it has released it to the microwave popcorn industry, the Seattle Post-Intelligencer recently reported.

The results must have been scary. One major maker, Pop Weaver, has removed diacetyl from its product, citing the EPA study as the reason, the Post-Intelligencer reports.

Others, however, have chosen to continue exposing workers and consumers to diacetyl. As the Post-Intelligencer makes clear, the additive "remains in widespread use in thousands of consumer products, including the microwave popcorn brands Orville Redenbacher and Act II."

Thanks to Liz Borkowski for alerting me to this story, and to the Project on Scientific Knowledge and Public Policy for trying to convince public-health agencies that their real constituency is the public, not the food industry.