By David Michaels
Updated Below

For the past several years, news articles and Congressional hearings have reported on a deadly, irreversible lung disease – bronchiolitis obliterans – that is caused by workers’ exposure to food flavoring chemicals, and more specifically by exposure to a butter-flavoring chemical called diacetyl. So far, attention has focused on worker exposure, rather than on possible health problems affecting consumers who pop popcorn in their microwave ovens. That focus may be changing, however, with a warning sent by one of the country’s leading lung disease experts.

The CDC, FDA, OSHA, EPA federal agencies charged with protecting public health each received a letter in July alerting them to the possible serious respiratory hazard to consumers who breathe in fumes from their artificially butter-flavored microwave popcorn. The warning should have resulted in some action by these agencies, but instead, they’ve done virtually nothing.

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.

In July, Dr. Cecile Rose, the chief occupational and environmental medicine physician at National Jewish Medical and Research Center, the most prestigious lung disease hospital in the country, wrote to the FDA, CDC, EPA and OSHA, informing the agencies of a patient she had recently identified

“with significant lung disease whose clinical findings are similar to those described in affected workers, but whose only inhalational exposure is as a heavy, daily consumer of butter flavored microwave popcorn.”

This letter is a red flag, suggesting that exposure to food flavor chemicals is not just killing workers, but may also be causing disease in people exposed to food flavor chemicals in their kitchens.

In the last seven years, dozens of workers have developed the rare and sometimes fatal disease bronchiolitis obliterans (BO) – also known as “popcorn lung.” The sick workers were employed in factories where diacetyl, the primary ingredient in artificial butter flavor, was manufactured or applied to food. Most of these cases have been seen in microwave popcorn factories. Last week, one of the country’s largest popcorn makers announced it was eliminating diacetyl from its butter flavor.

Since I first wrote about the failure of OSHA to protect food industry workers from this deadly exposure, I have been asked by dozens of reporters whether it is safe to pop microwave popcorn at home. I explain that there is no evidence that it is dangerous to breathe the chemicals that come out of popcorn bags after they are microwaved, but that the issue has not been studied, so I can’t say that it is safe. My colleagues and I at the Project on Scientific Knowledge and Public Policy have been doing our best to push the relevant federal agencies into investigating the problem.

We have not been alone. In the last year, the question of consumer exposure has come up in countless media reports and several congressional hearings, and a powerful member of Congress has raised the issue directly with the Commissioner of the FDA.

Given this background, one would expect the relevant federal agencies to respond quickly to what may be the first documented case of lung disease caused by consumer exposure to artificial butter flavor. What we are faced with, however, is a failure of those agencies to take action, a sign that something is seriously wrong with our public health system. The letter from Dr. Rose should have been sufficient to raise concerns at the agencies involved. There are few physicians in the country who have more experience with lung disease caused by food flavor chemicals than Dr. Rose; she has been a consultant to the Flavor and Extract Manufacturers Association (FEMA) the association of companies that make food flavorings for more than a decade and helped develop the industry’s Respiratory Safety Program.

Later in this post, I detail the response of each agency. First, it is worth looking at Dr. Rose’s letter, in which she described the ways in which this patient’s condition resembled that of the workers who developed lung disease after exposure to flavor chemicals, and the reasoning that went into her decision to alert the regulatory agencies:

1. The patient described progressively worsening respiratory symptoms of cough and shortness of breath. Extensive medical, occupational and environmental history taking did not reveal a known cause for these symptoms. The patient did report daily consumption of several bags of extra butter flavored microwave popcorn for several years.
2. Serial pulmonary function testing revealed progressively worsening fixed airflow limitation without a bronchodilator response and with a normal diffusion capacity for carbon monoxide. This is the pattern of lung physiologic abnormalities described in affected workers.
3. High resolution chest CT scan showed bronchial wall thickening, bronchiectasis, mosaic attenuation and expiratory air trapping. This appearance is similar to the imaging abnormalities reported in affected microwave popcorn factory workers.
4. Lung biopsy showed diffuse hyperinflation, a relative absence of small airways, and bronchioles in various stages of obliteration, findings of bronchiolitis obliterans (BO).
5. The patient’s clinical course has been consistent with that described in microwave popcorn factory workers with BO, with a progressive decline in FEV (Forced Expiratory Volume in the first second, a marker of airflow obstruction) despite treatment with oral corticosteroids. His lung function appears to have stabilized recently with cessation of exposure to butter flavored microwave popcorn.
6. We measured airborne levels of diacetyl during microwave popcorn preparation in the patient’s home and found levels similar to those reported in the microwave oven exhaust area in the quality assurance unit of the microwave popcorn manufacturing plant where affected workers were initially described.

This letter represents more than the report of a single isolated case of BO in a person who happens to eat a lot of extra-buttery microwave popcorn. The report comes after years of evidence that diacetyl causes BO in workers at factories where the chemical is produced, mixed and applied to food products. We don’t know, in other words, whether this is an unfortunate coincidence or the first identified case of BO among popcorn consumers. It is possible that there are other people who have BO or another, less severe diacetyl-caused obstructive lung disease, but who are being treated by their own personal physicians who do not have Dr. Rose’s expertise and familiarity with the outbreak of BO in food industry workers. Are there more cases out there? We don’t know, but now is the time to find out.

In her letter, Dr. Rose acknowledged that it is difficult to make judgments based on a single case, but, given “the public health implications” of the possibility this patient’s illness was caused by his exposure to butter flavor chemicals at home, she did what any dedicated public health practitioner would do: she notified the agencies that are supposed to protect the public health.

And that’s where things seem to have stopped.

The receipt of Dr. Rose’s letter is the moment where the FDA, or the CDC, should have said “Whoa! Here is an indication that the problem may go beyond workplaces.” The agencies have never looked for BO cases among people who are heavy consumers of popcorn at home, but now they could issue an alert, requesting information from lung disease specialists around the country. Or they could have called a meeting of the technical directors of the popcorn manufacturers to learn about what they know about consumer exposures, especially about the levels of diacetyl released when popcorn with extra butter flavor is popped in a microwave oven. (Documents released by the EPA suggest that ConAgra, manufacturer of the Orville Redenbacher brand, may know quite a lot.) At minimum, they could have asked Dr. Rose for more information.

None of the agencies did anything like this. In fact, their failure to respond adequately is a sign that our public health protection system is in dire need of repair.

Here’s a brief review of what each agency is doing (or not doing) about food flavor chemicals, and, according to Dr. Rose, how they responded (or didn’t respond) to the letter.

1. The Food and Drug Administration (FDA)

The FDA has been asked several times to examine whether breathing diacetyl poses a risk to consumers. Each time, the agency has refused. Last September, SKAPP petitioned the FDA to remove diacetyl from the “Generally Regarded As Safe” (GRAS) list, pointing out that “there is compelling evidence that breathing diacetyl vapors causes lung disease and there is no evidence of a safe exposure level.” In March 2007, the FDA wrote us back, essentially blowing us off.

Then, in May 2007, Congresswoman Rosa L. DeLauro (D-CT), chair of the House of Representatives Appropriations subcommittee that funds the FDA, urged the agency “to consider revoking the generally safe designation for diacetyl and removing it from the market until further testing is completed.” FDA Commissioner von Eschenbach refused to commit the FDA to do anything other than monitor the situation, and there is no evidence they are even doing this.

Frustrated by the FDA’s continued failure to take action, Rep. DeLauro added language to the report that accompanied the Agriculture Appropriations Bill, directing the FDA to submit a report on its diacetyl research plan to the committee within 90 days of enactment.

What did the FDA do when it received Dr. Rose’s letter in July? According to Dr. Rose, FDA attorneys asked that she resubmit her letter to the docket that has been created for our petition, since evidently, the FDA office to which the letter was sent didn’t feel they could do it themselves. (This is the reason the letter is dated July 18th but date stamped August 21, the day it was entered into the docket.)

2. The Environmental Protection Agency (EPA)

As readers of The Pump Handle know from repeated posts on the subject, some time in 2003, the EPA announced that a study on the chemicals released in the popping and opening of packages of microwave popcorn was underway and was expected to be completed by the end of that year (2003). The results of that study still have not been released, although the results have been shared with popcorn manufacturers.

In July 2006, I wrote to EPA Administrator Stephen L. Johnson, asking for expedited release of the study and objecting to the preferential treatment given to industry. The EPA responded that the study had undergone internal and external review and would soon be sent to industry “solely to ensure that no confidential business information is released.” The agency planned to submit the paper to a scientific journal in fall 2006 and anticipated publication by mid-2007.

The scientific community and the public are still waiting for the result. However, last week, the owner of one of the country’s leading popcorn manufacturers cited the EPA study as one of the reasons his firm was now selling a butter flavor popcorn made without diacetyl.

What did the EPA do when it received Dr. Rose’s letter in July? According to Dr. Rose, the EPA thanked her and said it would treat the letter as a submission under section 8e of the Toxic Substances Control Act. Under this law, the EPA collects and compiles reports on adverse effects of chemicals. At one time, the agency promptly posted them on its website so the reports could be read by interested parties. But the EPA has evidently stopped posting – the last 8e submission posted on the EPA website was submitted in June 2006. So Dr. Rose’s letter is apparently collecting dust in some large pile of paper where it apparently remains, unlikely to be released to the public for who knows how long.

3. The Centers for Disease Control and Prevention (CDC)

Although its mission is “to promote health and quality of life by preventing and controlling disease, injury, and disability,” the CDC is not a regulatory agency. It does play a central role in investigating the causes of illnesses and in alerting the public and medical communities about ways to prevent diseases from occurring.

The National Institute for Occupational Safety and Health (NIOSH), a branch of the CDC, has done terrific work investigating the causes of lung disease among flavor workers.

As of last week, CDC had not responded to the letter.

4. The Occupational Safety and Health Administration (OSHA)

OSHA is charged with protecting the health of workers, so the information in this letter wasn’t particularly relevant to their work. Last July, two unions petitioned OSHA for a standard that would protect workers from diacetyl exposure. Dozens of leading scientists supported the petition.

The failure of OSHA to take even minimal steps in the face of a clear and present hazard (dozens of sick workers in popcorn and flavor factories) has been the subject of scathing newspaper articles and editorials and two congressional hearings.

The House of Representatives will soon consider legislation, already passed by the House Education and Labor Committee, requiring OSHA to issue an emergency standard for diacetyl 90 days after the legislation is enacted. FEMA, the flavor industry’s trade association, supports the legislation.

The Bush Administration, needless to say, opposes the legislation, and there still is no indication OSHA is actually working on a standard. The only sign of life so far out of OSHA was the recent announcement of a “National Emphasis Program” aimed at popcorn factories. Given that most new cases appear to be occurring in the factories that produce the flavorings used in the production of popcorn and other food products, this is simply too little too late.

Perhaps because Dr. Rose’s letter did not contain any information that required OSHA to do anything (it was limited to a report on consumer rather than worker exposure), OSHA evidently did respond promptly, thanking Dr. Rose for her letter.

At one time, the US regulatory agencies were the envy of the world. The agencies were staffed with the best scientists, who did their best to ensure that preventable diseases were actually prevented.

Sadly, much has changed. The newspapers are filled with reports of political hacks running the agencies, over-ruling the decisions of career scientists in order to protect perceived corporate interests. The White House Office of Management and Budget has erected a series of barriers impeding those agencies that still want to issue any new measures that will protect the public from pollution and dangerous products.

The anti-regulatory fervor of the Bush Administration is so great that agencies like OSHA will not step in to regulate even when it is requested to by responsible industry, as in this case where the flavor industry supports legislation that will force OSHA to issue a diacetyl standard.

Sadly, the damage to the agencies has been severe. The anti-regulation policies coming from the White House and the political hacks running the agencies have taken their toll. The agencies have fewer staff and fewer resources. Morale is at its lowest. Many of the best scientists have left and are not being replaced.

The public will pay the price, for many years to come. Repairing our system of public health protection will be one of the most difficult challenges faced by the next Administration.

Update (9/4/07):
In statement issued today, FEMA has recommended that “its members who manufacture butter flavors containing diacetyl for use in microwave popcorn consider reducing the diacetyl content of these flavors to the extent possible.” Read the whole statement here.

Update (9/5/07):
 We’ve gotten several comments and emails about people who have experienced irritation or difficulty breathing when microwave popcorn is popped. If you are concerned about symptoms you are experiencing, you should discuss them with your doctor; OSHA has posted information that may be useful to physicians.

Also, you can submit comments to FDA as part of the docket dealing with our request to cancel diacetyl’s GRAS status until further research is completed. Reference Docket #2006P-0379, and send written comments to Dockets Management Branch (HFA-305), Food and Drug Administration, 5630 Fishers Lane, Room 1061, Rockville, MD 20852.

David Michaels heads the Project on Scientific Knowledge and Public Policy (SKAPP) and is Professor and Associate Chairman in the Department of Environmental and Occupational Health, the George Washington University School of Public Health and Health Services.