The North Dakota governor's office on Thursday became the latest in a string of state executives to receive mail containing a suspicious white powder, which authorities say is not harmful, law enforcement and state health officials said Thursday.

A staffer in the governor's office first found the powder-laced envelope Thursday morning at about 10:30, said Michael Gerhart of the North Dakota Highway Patrol.

The Bismarck Fire Department arrived on the scene at 11 a.m. in protective hazmat suits, retrieved the letter for testing and deemed the unidentified white powder as benign. The North Dakota Department of Health later conducted preliminary tests and said the powder was not harmful.

The white envelope was found on the first floor of the governor's office in the state Capitol and had a return address from Texas, said Don Canton, a spokesman for Gov. John Hoeven.

Authorities evacuated staff and relocated them to the governor's second-floor office. Hoeven was not in Bismarck on Thursday, Canton said.

State health officials advised workers who were in the vicinity of the letter to go home, change clothes, take a shower and put their clothes in a plastic bag, Canton said.

"Everybody responded very professionally. There are protocols in the offices for events like this," Canton said. "We followed the protocol."

A bleach-and-water solution was used to clean the area where the letter was found, said Kermit Schaefer, the assistant fire chief for the Bismarck Fire Department.

The health department is still performing tests on the white powder, state epidemiologist Kirby Kruger said.

"Right now, the tests are still being run to determine what it may be." He said results were to be finalized sometime Thursday night.

Gerhart said the Federal Bureau of Investigation will take over the investigation.

More than a dozen other states have received similar envelopes with a suspicious white powder this week, including Alabama, Alaska, Hawaii, Maine, Michigan, Minnesota, Mississippi, Missouri, Montana, Oklahoma, Rhode Island, Texas, South Carolina and Georgia, according to the Associated Press.

Gerhart said no connections can be made right now among those cases and the envelope sent to Hoeven's office.

(Reach reporter Brian Duggan at 223-8482 or brian.duggan@;bismarcktribune.com.)