A haz-mat call brought West Des Moines firefighters on Friday to the local offices of the federal Social Security administration. Spokesman Mark Adams says it was a report of a granular substance on an envelope. Firefighters arrived and called in Des Moines haz-mat, and also had workers from the Federal Protective Services on hand since it was a federal office. They tested but had too little of the substance to learn much, except that it was not a hazard. The mystery substance was not inside the envelope reported in the office mailroom. They said, actually, that they saw “a little bit of powder, a granular substance,” on the mail. It took only three hours to secure the site, test the substance, pack the gear and return to headquarters. While there may have been no need to decontaminate people, Adams says the team went through the usual preparations. They set up for everything, just as they normally would do. There have been several mysterious-powder scares that turned out to be nothing this year, but Adams says the fire and haz-mat professionals will never brush off such a report. They have to take every threat like this to be credible until it’s proven otherwise. Adams says “If you just let it go then the worst could probably happen.” More than 350 workers were kept inside the building until tests were complete and the all-clear was given.