A suspicious odor – resembling natural gas – forced more than 200 people from the Desert Diamond Casino on South Nogales Highway Friday morning, an official said.

When firefighters arrived about 7:30 a.m. they were able to detect the odor, but its source was never discovered, said Drexel Heights Fire District Assistant Chief Gary Bynum.

A Southwest Gas technician technician went to the casino to investigate the smell but was unable to detect any natural gas, said spokeswoman Libby Howell. Even after shutting down all of the gas mains and then turning them on again to conduct tests, no leaks were found, she said.

Both the casino and hotel at 7350 S. Nogales Highway, about a mile south of Valencia Road, were evacuated. Eighty people from the casino, 45 from the hotel and 105 employees had to leave the facility, Bynum said.

They were allowed to re-enter the casino about 11:30 a.m., Bynum said.