The California Occupational Safety and Health Appeals Board on Monday upheld citations issued to Barrett Business Services Inc. (NASD: BBSI), a provider of staffing and professional employer organization services. The citations stemmed from a carbon monoxide exposure event in 2011 that sent eight temporary workers to a hospital.

The staffing buyer in the case, L&L Foods, settled its side of the case in April 2013, but an administrative law judge imposed civil penalties of $80,050 on Barrett, which it contested.

For months prior to the incident the workers contracted by Barrett to package fruits and nuts in L&L Foods’ warehouse in Anaheim, Calif., had complained to their supervisor that they were experiencing headaches, nausea and other health issues caused by forklifts operating in an enclosed area, according to the department. However, neither the staffing company nor host employer L&L Foods took any action.

On the day of the incident, a forklift driver became ill and was hospitalized for carbon monoxide poisoning, while seven other workers were taken to the hospital for treatment, according to the department. Cal/OSHA tested the facility and found the workers were exposed to CO levels of 250-350 parts per million which exceeded the ceiling limit of 200 parts per million.

The evidence found that L&L Foods had sealed all of the vents at the facility to prevent vermin from entering the establishment, according to the department. Barrett did not assess the safety conditions for the enclosed environment, failed to control the increased carbon monoxide levels in the workplace and continually disregarded worker’s reports of headaches and nausea from the fumes.

“This decision by the Appeals Board underscores the shared responsibility by staffing companies and host employers in protecting workers’ health and safety,” said Cal/OSHA Chief Juliann Sum. “This was a case where neither employer addressed known safety and health hazards.”