Six cyclists with the AIDS/LifeCycle ride were treated for eye irritation Thursday after passing by the Federal Correctional Institution in Lompoc.
Eric Jost with AIDS/LifeCycle says the reports were received by command center staff at about 11 a.m.
The cause was reportedly due to tear gas set off during a training exercise at the prison.
Jost said, "According to the penitentiary’s warden, Steve Langford, the tear gas was set off near the route as part of a training exercise conducted on the range. Warden Langford explained that the wind shifted the direction of the tear gas toward the road. After our inquiry, Warden Langford cancelled the training immediately. He expressed his sincerest apologies for the incident."
The cyclists affected were treated by the AIDS/LifeCycle on-ride medical team.
On Wednesday, two riders were injured as the ride passed through San Luis Obispo County.
One of the cyclists crashed along Highway 1 just south of Highway 46 and broke his collarbone, according to CHP.
The other cyclist was heading toward Highway 1 from Highway 46 when he rode over a ruble strip and was thrown from his bike, according to CHP. He was airlifted to a nearby hospital.
The 545-mile ride started in San Francisco Sunday and will end in Los Angeles on Saturday.
Participants have raised more than $16 million — a record amount — to support the San Francisco AIDS Foundation and the HIV/AIDS-related services of the Los Angeles LGBT Center.