Authorities say 22 people, most of them schoolchildren, fell ill at a Catholic church in Southern California and were taken to a hospital.

Officials initially suspected carbon monoxide poisoning had caused two children to faint and several other people to become nauseated and dizzy during a school Mass Friday at Sacred Heart Catholic Church in Coronado.

But Kim Edwards, a University of California, San Diego Medical Center spokeswoman, says tests run on the 17 children and five adults taken to the hospital found no elevated carbon monoxide levels or any other toxic substance.

Coronado Fire Division Chief Ed Hadfield says hazmat teams and a San Diego Gas & Electric crew looked for a source of carbon monoxide or a furnace leak but couldn't find any evidence of airborne contaminants.