Governor Bev Perdue's Press Secretary Chrissy Pearson says the governor was inside the building, but was on another floor signing a bill when the envelope was opened.
Authorities say at least two people in the small contained area were exposed to the substance.
"We had two staffers who were potentially exposed; again we're hopeful that this is nothing more than baby powder but taking the appropriate steps," Pearson said.
Officials evacuated the building as a precautionary measure. They say there was a bill signing going on, so the building was not heavily occupied.
Raleigh resident Jim Sweeney and his group barely made it through the door when he saw the governor leaving the building. Sweeney says he was told he should do the same.
"We were going to tour the Capitol a friend of ours was going to tour the Capitol," Sweeney said. "We were just walking in and just happened to bump into her."
Hazmat team members suited up to retrieve the envelope and officials say they carefully walked it out hours later.
ABC11 has learned that the envelope was sent to the state lab and it could be days before we know what was inside.
Monday was the first time the capitol building has been evacuated since the governor took office, but Sweeney says he wasn't surprised by what he saw it's certainly not the first time a government building receives a suspicious envelope.
"This kind of stuff happens all the time," Sweeney said.
Capitol police sealed off the building Monday afternoon and is expected to re-open sometime Tuesday.