Four floors of the Des Moines Register building in downtown Des Moines were evacuated this morning after the discovery of an envelope containing a suspicious powder. The suspicious brown, granular substance fell out of a standard-sized business envelope that was opened after it was delivered from the mail room. A hazardous materials team shut down the block in front of the building and set up a blue tent. Five employees who came into contact with the powder were taken into the tent and washed down to decontaminate them.Des Moines Fire Department spokesman Brian O’Keefe says they’re all okay. He says they’re all doing fine and their only complaint was the water was too warm when they took their showers. O’Keefe says terrorism experts examined the trhee-page letter. He says they said the person was knowledgeable and there were no mistakes. He says the letter was general and directed at U-S policy and was not directed at the President or any media outlet. O’Keefe talks about the substance. He says the HAZMAT crew described the substance as similar to brown sugar, but it was more granular in nature. He says there was a total of about four teaspoons in the envolope. He says tests by a military team came up negative for any dangerous chemicals. The other employees were allowed to re-enter the building early this afternoon after the HAZMAT on-site issued the “all-clear.” Police are studying the letter to try and determine its origin.