CO2 fumes sicken workers at Bay Area plant VALLEJO, Calif., March 30 (UPI) -- Firefighters said as many as 100 workers at a San Francisco-area food processing plant were sickened by leaking carbon dioxide Friday. The incident took place in Vallejo around 12:30 p.m. PDT but apparently didn't cause any serious injuries. The Vallejo Fire Department told KTVU-TV in San Francisco that emergency crews set up a triage area outside the plant to treat the victims, most of whom complained of shortness of breath. An unknown number were transported by ambulance to nearby hospitals. The cause of the leak wasn't immediately known.