Mere days after a death threat was made against David Letterman on an Al Qaeda website, an envelope containing white powder was delivered to the L.A. offices of ‘The Late Late Show With Craig Ferguson.’

The powder was suspected to be anthrax, but police later deemed it harmless. Two show staffers were exposed to the substance, but were released after a brief period of observation.

Ferguson treated the incident humorously during his monologue on Tuesday night’s show. “It’s a frightening day here at the studio,” he said. “Today someone sent here an envelope packed with white powder. I said, ‘I’ll test it for you if you want.’ I have a special test that I conducted between 1979 and 1992.”

“I was going to come out and talk about the earthquake, but I can’t do that now,” continued Ferguson, referencing the earthquake which rattled the East Coast yesterday. “Because the earthquake only scared millions of people on the East Coast, but the white powder did something much worse — it scared me.”

[The Late Late Show With Craig Ferguson]