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Diacetyl / Popcorn Workers Lung

What it is: Dozens of workers around the country have developed the debilitating lung disease bronchiolitis obliterans, also known as “popcorn workers lung,” and other respiratory illnesses from exposure to vapors from diacetyl, a component of artificial butter flavor used in microwave popcorn and many other food products.

Where policy stands: The National Institute for Occupational Safety and Health (NIOSH) conducted several studies that confirmed the link between occupational exposure to artificial butter flavoring and lung diseases. In 2000 they issued recommendations to a Missouri microwave popcorn plant about protecting workers from this hazard, and in 2003 they sent an alert recommending safeguards to 4,000 businesses that might use or make butter flavoring.

The Occupational Safety and Health Administration (OSHA), which has the authority to regulate workplace hazards, has failed to turn these findings and recommendations into regulation that would protect workers in facilities using diacetyl.

Recent events: On July 26th, 2006, the United Food and Commercial Workers Union (UFCW) and the International Brotherhood of Teamsters petitioned OSHA to issue an emergency temporary standard to protect workers from diacetyl and to begin the process of protecting workers from other hazardous flavoring chemicals. Unions also petitioned Cal-OSHA (the state equivalent of the federal agency) to take these steps.

A group of 42 top scientists and occupational health experts sent a letter to Labor Secretary Elaine Chao in strong support of the unions’ petition.

SKAPP also asked the Environmental Protection Agency to release the results of its study on consumer exposure to diacetyl vapors released from microwave popcorn bags, and petitioned the Food and Drug Administration to revoke diacetyl's "generally regarded as safe" (GRAS) status. FDA responded that that the agency had not reached a decision on the petition "because of the limited availability of resources and other agency priorities." 

In August of 2006, UFCW, Western States Council, and the California Labor Federation petitioned Cal/OSHA to adopt an emergency temporary standard for diacetyl in California. SKAPP Director David Michaels wrote a letter about the toxicity of diacetyl for inclusion in Cal/OSHA's record.

In March 2007, California Assemblywoman Sally Lieber introduced a bill that would ban diacetyl in the workplace by 2010, and Cal/OSHA drafted a standard on occupational exposure to food flavorings.

In May 2007, Congresswoman Rosa DeLauro wrote to FDA Commissioner Andrew von Eschenbach, also requesting a re-examination of diacetyl's GRAS status. Von Eschenbach responded that "the agency does not have evidence that would cause it to take immediate action with respect to diacetyl" and that "FDA continues to monitor the scientific literature for studies conducted to define and clarify the dangers associated with exposure to diacetyl vapors."

In 2007, Congresswoman Lynn Woolsey introduced legislation that would require OSHA to set an interim and final standard (within six months and two years, respectively) for occupational exposure to diacetyl. The House passed the legislation on September 26, 2007.

Further Details:
Read “A Case of Regulatory Failure: Popcorn Workers Lung” (case study)
Read SKAPP’s July 26th press release (html or PDF)
View a list of studies and other documents related to popcorn workers lung
Read a fact sheet on diacetyl (PDF)
View links and resources from the California nonprofit WorkSafe

Related News Stories:
Stories About Affected Workers:
Baltimore Sun, April 23, 2006, “Disease is Swift, Response is Slow: Government lets flavoring industry police itself, despite damage to workers' lungs
Sacramento Bee, July 30, 2006, “Flavoring Agent Destroys Lungs: Two workers need transplants; threat could be widespread"
Sacramento Bee, September 4, 2006, “Flavoring Suspected in Lung Disease cases: Up to 5 factory workers may suffer from illness that destroys tiny airways; federal probe launched

Stories About July 2006 petition to OSHA:
* Associated Press, "Union Seeks 'Popcorn Lung' Safeguards"
 * Baltimore Sun, "Federal Measures Sought to Combat Flavoring Peril"
 * Cleveland Plain Dealer, "Groups Want Popcorn's Butter Flavoring Regulated"
 * Los Angeles Times, "Limits Sought on Worker Exposure to Flavor Agent"
 * Reuters, "US unions seek limit on butter flavor ingredient"
 * Sacramento Bee, "Food Plant Safety Faulted"

Related Documents (PDF format):
* Scientists’ letter to Secretary of Labor Elaine Chao
* UFCW and IBT petition to Secretary Chao
* SKAPP’s letter to EPA Administrator Stephen Johnson and EPA's response
* UFCW’s petition to the National Toxicology Program
* AFL-CIO's letter to OSHA Assistant Secretary Edwin Foulke and OSHA's response
* Letter to Secretary Chao from US Representatives Miller, Owens, and Solis
* Diacetyl poster from product defense firm ChemRisk
*  Labor union petition to Cal-OSHA
* State Senator Richard Alarcon's letter to Cal-OSHA and Cal-OSHA's response
* SKAPP's petition to FDA to revoke diacetyls' GRAS status and FDA's response
* SKAPP's letter to Cal-OSHA on diacetyl's toxicity
* Statements from California Assemblywoman Sally Lieber for information and legislative hearings on the proposed workplace diacetyl ban
* Cal/OSHA draft standard on occupational exposure to food flavorings
 * National Toxicology Program's Chemical Information Review Document for Artificial Butter Flavoring and Constituents
* Letter from ConAgra to EPA regarding emissions from microwave popcorn bags (also see ConAgra's initial meeting request; emails regarding a meeting between ConAgra and EPA staff; and the plant confidentiality agreement)
* U.S. Representative Rosa DeLauro's letter requesting FDA reconsider diacetyl's GRAS status, and FDA Commissioner Andrew von Eschenbach's response
* Testimony of Eric Peoples, a former popcorn worker with bronchiolitis obliterans, at a House subcommittee hearing "Have OSHA Standards Kept up with Workplace Hazards?"
* Letter from Adam Finkel, former Director of Health Standards Programs at OSHA, to Congresswoman Woolsey in response to the House subcommittee hearing
* Legislation introduced by U.S. Representative Lynn Woolsey (also see Woolsey's statement, and letters from OSHA Assistant Secretary Edwin Foulke, the American Bakers Association, and the industry group OSHA Fairness Coalition regarding the bill)
* Markup of HR 2693
* Letter from Cecile Rose of National Jewish Medical and Research Center to FDA
* Letter from unions and scientists to Secretary of Labor Elaine Chao renewing their call for emergency action to protect workers

Blogs: Read the latest on diacetyl at The Pump Handle blog


March 12, 1985: NIOSH investigators visit an Indiana facility that produces flavors for bakeries, where two young, previously health, nonsmoking employees have been diagnosed with severe fixed obstructive pulmonary disease (consistent with bronchiolitis obliterans). Diacetyl is one of the chemicals commonly used at the facility.

February 16, 1993: Researchers for the German company BASF finish conducting a study in rats underwent a single 4-hour exposure to diacetyl vapors; all of them died at diacetyl concentrations > 23.9 mg/l.

May 19, 2000: Missouri Department of Health notifies OSHA that ten workers from one popcorn plant have bronchiolitis obliterans and asks OSHA to inspect the facility.

May 23, 2000: OSHA inspector visits the plant, but samples cannot be analyzed by OSHA’s laboratory.

August – November 2000: NIOSH investigates Missouri microwave popcorn facility; findings indicate that workers exposed to flavorings at the microwave popcorn plant are at risk for developing fixed obstructive lung disease.

December 2000: NIOSH issues interim recommendations to the Missouri microwave popcorn plant on ways to control workers’ exposure to the artificial butter flavoring

September 2001: NIOSH investigators return to the Missouri factory they studied to distribute materials describing investigation results, ongoing activities, and worker precautions.

September and December 2001: Attorney representing sick workers files complaints with OSHA, noting that worker health continued to decline after plant took measures recommended by NIOSH.

April 26, 2002: Scientists from NIOSH and the Missouri Department of Health publish an article in CDC’s Morbidity and Mortality Weekly Report describing their investigation; the article notes that "recent reports to CDC document bronchiolitis obliterans cases in the settings of flavoring manufacture" and that "preliminary animal studies at CDC suggest severe damage to airway epithelium after inhalation exposure to high air concentrations of a butter flavoring."

September 2002: OSHA’s Region VII enters “an agreement establishing an alliance” with the Popcorn Board trade association; the agreement includes a provision for the Board to review a draft OSHA “Hazard Information Bulletin.”

2002 - 2003: NIOSH scientists conduct experiments on laboratory animals and find significant adverse respiratory effects from diacetyl vapor exposure.

March 2003: The alliance between OSHA and the Popcorn Board concludes, evidently without the Hazard Information Bulletin being issued.

Spring/Summer 2003: EPA’s Indoor Air Quality Research Update reports that a project to identify and quantitatively evaluate compounds emitted through popping and opening microwave popcorn is expected to be completed in December 2003.

December 2003: NIOSH alert suggesting safeguards and asking employers to caution workers goes out to 4,000 businesses that might use or make butter flavoring.

July 26, 2006: UFCW and the Teamsters petition OSHA to issue an emergency temporary standard to protect workers from diacetyl. Forty-two scientists and occupational health experts express support for the petition.

July 26, 2006: SKAPP requests the EPA to release the results of its study that had been slated for completion in December 2003.

August 21, 2006: UFCW, Western States Council, and the California Labor Federation petition Cal/OSHA to adopt an emergency temporary standard for diacetyl in California.

March 2007: California Assemblywoman Sally Lieber introduces a bill that would ban diacetyl in the workplace by 2010, and Cal/OSHA drafts a standard on occupational exposure to food flavorings.

May 7, 2007: Congresswoman Rosa DeLauro writes to FDA Commissioner Andrew von Eschenbach requesting that the agency re-examine diacetyl's "Generally Regarded as Safe" status.

June 12, 2007: FDA Commissioner Andrew von Eschenbach responds to DeLauro's request, stating that "the agency does not have evidence that would cause it to take immediate action with respect to diacetyl" and that "FDA continues to monitor the scientific literature for studies conducted to define and clarify the dangers associated with exposure to diacetyl vapors."

June 13, 2007: Congresswoman Lynn Woolsey introduces legislation that would force OSHA to set an interim standard for diacetyl exposure within six months and a final rule in two years.

August 28, 2007: Manufacturer Pop Weaver announces that it has eliminated diacetyl from its microwave popcorn.

September 4, 2007: David Michaels breaks the news, on The Pump Handle blog, that Dr. Cecile Rose, chief occupational and environmental medicine physician at National Jewish Medical and Research Center, had diagnosed a case of bronchiolitis obliterans in a man who did not have occupational exposure to diacetyl but was a regular, heavy consumer of microwave popcorn. She had informed the FDA, EPA, CDC, and OSHA about the case in July but gotten very little response. Newspapers and TV shows across the country publicize the story, and ConAgra announces that it will remove diacetyl from its Orville Redenbacher and Act II microwave popcorn lines.

September 26, 2007: By a vote of 260 to 154, the U.S. House of Representatives passes the Popcorn Workers Lung Disease Prevention Act, which requires OSHA to set a standard to protect workers from diacetyl.

September 24, 2008: Senators Brown (OH), Kennedy (MA), McCaskill (MO), and Murray (WA), send letter to Secretary Chao and A/S Foulke asking for information and update on status of OSHA's efforts to protect workers from diacetyl (here)