RICHMOND (CBS SF) – The fire at a Richmond scrap metal yard that triggered an overnight shelter in place for several neighborhoods earlier this week released benzene into the air, officials revealed on Friday.

CCHS Environmental Health Director Dr. Marilyn Underwood said that air samples taken by the Bay Area Air Quality Management District at Sims Metal Management in close proximity to the fire found a high presence of benzene, a known carcinogen.

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“While long-term exposure to benzene can cause cancer, the health impacts of short-term exposure to the levels found during the fire are not known,” Underwood said in a release.

Both the air district and country hazmat team also measured high particulate readings throughout the night as the fire continued to spiel out thick black smoke.

Officials said smoke particulates can irritate the throat, lungs and eyes, particularly in those with pre-existing lung disease such as asthma.

“All smoke is toxic and all smoke contains particulate matter,” said Dr. David Goldstein, CCHS Deputy Health Officer. “Anytime we see smoke we should take precautions in order to minimize exposure.”

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Health officials said monitors in North Richmond, Atchison Village, and Point Richmond and fenceline monitors at the Chevron Refinery were also analyzed. They said elevated particulate readings were found by the Point Richmond community air monitor.

However, there were no other elevated readings of any other chemicals that were analyzed or particulates on any of the other monitors.

A shelter in place was issued Tuesday night for an area that spanned from 23rd Street to Harbour Way and Wright Avenue to Ohio Avenue in Richmond. It was later extended to Atchison Village and the Iron Triangle in North Richmond.

The order was lifted after the fire was under control just before 4 a.m. on Wednesday.

If people have concerns about the impact the smoke may have had on their health, they should contact their healthcare provider, Goldstein recommended.

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The fire at Sims Metal Management, located at 600 S. 4th Street in Richmond, started on Tuesday around 5 p.m. The cause of the fire is still under investigation.