“The FBI, police and paramedics scrambled throughout the District on Thursday afternoon chasing reports of letters containing a suspicious white powder and mailed to 28 D.C. public schools in all quadrants of the city, authorities said.
Initial tests found no toxic substance in the items that arrived in office areas and mailrooms, and ‘no students have been in danger at any point,’ said Pete Piringer, a spokesman for the D.C. Fire and EMS Department. Piringer said that as of late Thursday afternoon, nobody at the locations had to be treated or taken to a hospital.”
(White powder sent to D.C. schools; substance not thought to be toxic – The Washington Post)