Area media are reporting that four dozen shuttle drivers at the Coachella Valley Music and Arts Festival fell ill during the weekend from what is believed to be a foodborne source.

The incident did not involved any of the attendees, according to a statement released by local health officials. It is believed that the shuttle bus drivers ate at a common facility wher meals were provided for them. Officials say the catering was unaffiliated with the festival but they have not yet identified the provider of the food.

Drivers came from a wide area, so there could be additional sick people who did not seek treatment at the hospitals closest to the event, according to statements from public health investigators on Tuesday.

News Channel 3 reported 23 drivers were treated at Eisenhower Hospital; 12 at Desert Regional Medical Center; and 11 at JFK Memorial Hospital.

“Our objective, if we can, is to find the source of the illness,” Riverside County spokesperson Jose Arballo said a statement to media “Part of this is also interviews with those who became ill to try and get a good idea of what might be the source of the sickness.”

Riverside County officials are working with public health departments throughout Southern California and the California Department of Public Health about the incident so potential patients can be interviewed.

“This could involve hundreds of interviews, but it is important to gather as much information as possible so that we can determine what happened and try to prevent it from happening again,” said Kim Saruwatari, director of Riverside County Public Health.

The drivers had nausea, vomiting, and other symptoms consistent with food poisoning.