Authorities: Substance in letter mailed to Durham building poses no threat

The Durham County Sheriff's Office says a powdery substance mailed to the North Carolina State Education Assistance Authority on Monday was not harmful and poses no health risk to the public.

The city's Bio-Chemical Emergency Response Team responded to 10 T.W. Alexander Drive Monday morning and secured the area after authorities received a report about the substance.

Authorities said the letter was addressed to someone who is not an employee of the NCSEAA. The source of the letter remains under investigation.