A federal investigation into the hazards facing cooks exposed to diacetyl, a sometimes deadly artificial butter flavoring, is under way in New York City restaurants while in Seattle, state worker-safety agents are starting a similar inquiry, according to theSeattle Post-Intelligencer.

These health evaluations come as two major federal studies confirm that even short exposures to the artificial flavoring can cause tissue damage.

Three teams of physicians and industrial hygienists from NIOSH took samples last week of the cooking oils and sprays being used and the air inhaled by cooks and other workers at kitchens in the Manhattan financial offices of JPMorgan Chase and Goldman Sachs.

The cooks are employees of Aramark, an international corporation running 3,500 food service operations in the U.S.

NIOSH launched the investigation at the request of Unite Here, a union representing 440,000 hotel, restaurant and hospitality industry workers.

"A government study like this is long overdue," said Eric Frumin, director of occupational safety and health for the international union. "Cooks throughout the country are breathing oil mist for hours every day. It's unknown how much diacetyl they're inhaling with it and that's what we hope NIOSH will determine."

The union requested the study after theSeattle Post-Intelligencerpublished in December the results of laboratory analysis of almost two dozen butters, margarines, oils and sprays used by home and professional cooks. Cooking was simulated and the air coming off the skillets and grill surfaces was collected and measured for diacetyl. The chemical flavoring agent was found in everything tested, with the highest level in the oils, sprays and butters used by professional cooks.

“We don't know at this time whether the cooks in these Aramark facilities have or do not have increased risk of respiratory disease,” said Fred Blosser, NIOSH's chief of public affairs. “The investigators hope to learn more through medical testing, which has been scheduled for the end of the month.”