SOUTH GATE, Calif. -- She was once in constant motion; her co-workers compared her to a roadrunner because of the way she darted around the workplace. But now Irma Ortiz sits at the edge of her couch, too winded to sweep her patio or walk her son to school without resting. She is slowly suffocating.

Ortiz, 44, is among a group of California food-flavoring workers recently diagnosed with bronchiolitis obliterans, a rare and life-threatening form of fixed obstructive lung disease. Also known as popcorn workers lung, because it has turned up in workers at microwave-popcorn factories, the disease destroys the lungs. A transplant is the only cure.

Since 2001, academic studies have shown links between the disease and a chemical used in artificial butter flavor called diacetyl. Flavoring manufacturers have paid out more than $100 million as a result of lawsuits by people sick with popcorn workers lung over the past five years. One death from the disease has been confirmed.

But no federal laws regulate the chemical's use. The Occupational Safety and Health Administration is still deciding what standards to set for workers who handle it. In late April, the head of OSHA, Assistant Secretary of Labor Edwin G. Foulke Jr., testified before Congress that the agency will begin inspecting microwave-popcorn factories this month.

While critics charge that OSHA has stalled, California is moving ahead. Here, state Assemblywoman Sally Lieber (D) has introduced a bill to ban the use of diacetyl.

Since the first California case of popcorn workers lung was diagnosed just over two years ago, state health officials have screened workers at each of the state's 29 food-flavoring plants, looking for breathing trouble. The screenings lay the groundwork for state regulation of diacetyl and provide the first comprehensive data on flavoring workers outside popcorn plants.

So far, the California Division of Occupational Safety and Health, or Cal/OSHA, has found eight flavoring workers with fixed obstructive lung disease, most of those with bronchiolitis obliterans. Twenty-two more have below-normal lung capacity, which may be the beginning of the disease.

"They're finding it there because they're looking there," said David Michaels of the department of environmental and occupational health at George Washington University. Michaels, assistant secretary of energy in the Clinton administration, accuses OSHA of "regulatory paralysis."

"It's not some carcinogen where you get cancer 30 years from now or something. The people are dying right in front of you," Michaels said. "You can't wait until you have all the evidence. You have to regulate it."

Even less is known about the health effects of eating diacetyl in butter-flavored popcorn, or breathing the fumes after the bag is microwaved. The Environmental Protection Agency has studied the fumes but is waiting for the industry to review the study before releasing it. The Food and Drug Administration has diacetyl on its list of substances "generally recognized as safe" but has not studied it.

California does not regulate the chemical's use, either. But, "in general, these employers know they have a problem. They're in a mode now where they're saying, 'Tell us what to do,' " said Len Walsh, acting director of Cal/OSHA. Using the chemical in closed containers instead of mixing it in the open air would help, Walsh said.

Ortiz said she wore a disposable face mask when she mixed flavors during the eight years she worked at Carmi Flavor and Fragrance Co. in Commerce, Calif. In recent years, it became impossible for her to wear the mask because she coughed continually at the plant and her nose often ran, Ortiz said.

Most of the California workers with irreversible obstructive lung diseases are, like Ortiz, young Latinos with no history of smoking, Walsh said. It can be hard to persuade them to take the disease seriously, he said.

"They don't believe they've got a problem because they only feel mild effects," Walsh said. "They want to keep their jobs."

Ortiz kept working until one day in December 2005 when she felt, she said, "I put all my strength into the job and I can't do no more." Ortiz is petite and birdlike; her black hair shows no streaks of gray.

"Before, I used to do a lot of exercise. I ran from place to place," she said, her sentences broken into panting phrases as if she were hiking a steep hill. Now, she does not like to be in public because long, body-shaking coughing fits could overcome her at any time. On Christmas, "I tried to dance with my brother, but not even five minutes," she said.

The loss of her $17-an-hour job makes keeping up with house payments difficult, said Ortiz's husband, Victor Mancia.

They are waiting for a lung transplant. "I was perfectly fine when I started," Ortiz said. "I want to be the same. But my doctor says I'm not going to be the same."