An unknown substance which sparked an alert at the CBS studios in Los Angeles was later determined to be talcum powder.

ABC spokeswoman Amy Astley confirmed that an envelope containing white powder was delivered to the Dancing With The Stars production office on the CBS studios lot on Friday night.

The statement said ABC was later told by Los Angeles fire officials that the substance was talcum powder.

FBI spokeswoman Laura Eimiller said hazardous materials officials from the city of Los Angeles, LAPD and FBI went to the scene after a report of a threatening letter containing white powder.

She said an initial screening indicated that the substance was not dangerous, but the letter was being transported to a regional laboratory for further testing.

She said the FBI and LAPD were investigating.