Several first-responders were sickened in San Francisco while attempting to help a motorist who passed out on the iconic Golden Gate Bridge, authorities said Monday.

The incident unfolded at about 11:45 a.m PT on Sunday with reports of an impaired driver stopped in northbound lanes of the famous span of U.S. Highway 101 that connects San Francisco to Marin County, the California Highway Patrol said.

The responding officers smelled “what we believe is fentanyl,” CHP Officer Andrew Barclay told NBC News, and the driver was immediately treated with the narcotic overdose spray Narcan “to bring him back.” Fentanyl is a powerful synthetic opioid that can be fatal even in small doses.

A short time later, the CHP officer who entered Shaw’s car to turn off the ignition became violently ill, fell to ground and “began convulsing and vomiting,” according to Barclay.

That officer was also given Narcan and Barclay said that treatment “likely saved his life.”

Later, a tow trucker driver, three more CHP officers and a Golden Gate Bridge patrol officer also fell ill and were treated at a hospital on Sunday, officials said.

All of those first responders had been released from the hospital by Sunday night, authorities said.

A hazmat team from the Mill Valley Fire Department decontaminated the car and several CHP cruisers that had responded.

“Once it’s determined that it’s a possible Fentanyl call, we have to treat it just as we do with all other infectious diseases or chemicals,” said Mill Valley Fire Chief Scott Barnes told NBC Bay Area. “We have to wear proper equipment, otherwise we become the victim.”

The 32-year-old man in the car was booked on suspicion of misdemeanor DUI before his release Sunday night, according to the San Francisco Sheriff’s Office and CHP.