A sulphuric acid leak at the Solvay chemical plant in California earlier this week has made about 70 people ill, Reuters reports.

A malfunctioning scrubber machine at the Carson, Calif., chemical company caused the leak, according to Los Angeles County Fire Department official Phil Ulloa. Ulloa told Reuters 13 people in the Carson area were treated at hospitals after complaining of nose and throat irritation and vomiting. All 13 were later released.

Reuters says it was not immediately clear if there were any workers at the Solvay plant when the leak occurred.

Last month, the US Department of Labor’s Occupational Safety and Health Administration launched two new web resources that aim to safeguard workers from exposure to hazardous chemicals in response to its own out-of-date standards. The government agency’s exposure standards, which were developed in the 1970s, are out-of-date and inadequately protective for the small number of chemicals that are regulated in the workplace, OSHA says.