HAYWARD -- Authorities evacuated the Hayward police station on Wednesday after authorities said an employee opened an envelope that contained a mysterious white powder.

The substance, police said, turned out to be a non-toxic household item commonly used to kill bugs.

Hayward fire crews and the Alameda County hazardous materials team responded at 10:45 a.m. to the station on West Winton Avenue after a clerk opened an envelope and saw the powder on her hand, said Lt. Mark Stuart.

No other employees came in contact with the powder, Stuart said, and fire crews flushed the substance off from the clerk's hand.

Crews soon determined the substance was Boric acid, which is commonly used in pesticide, Stuart said.

No one was injured and the incident remains under investigation.

Anyone with information about the hoax is asked to call police at 510-293-7000.

Contact Natalie Neysa Alund at 510-293-2469. Follow her at Twitter.com/nataliealund.