Two city buildings, including City Hall, were locked down in the middle of the day Tuesday after employees found a yellow powder on two packages, according to a news release.

Employees were not allowed to leave either City Hall or the city's water office, 801 W. San Mateo Road, between about 10 a.m. and 12:30 p.m., until Fire Department personnel tested the substance and deemed it harmless, according to the release from city spokeswoman Laura Banish. Streets around City Hall also were closed.

A mailroom employee noticed the package with a yellow-colored powder on the outside just before 10 a.m. and notified police. The package had been sent from the U.S. Post Office, located across from City Hall on South Federal Place, and contained shipping supplies, the release says.

Employees at the city's Sangre de Cristo Water Co. picked up another package at the city mailroom Tuesday morning and took it back to the water company building before noticing the yellow powder on the outside of the package, the release states.

Members of the Fire Department's hazardous materials team tested the substance three times with a biological identity reader and came up with three negative tests, said Santa Fe Assistant Fire Chief Charlie Velarde.

Velarde said he didn't know what exactly the powder was and speculated it might have been "toner powder" or powder sometimes used to soak up moisture in packaging. The postal inspector took custody of the box, he said.

The powder allegedly had the consistency of dried mustard, according to the news release. Velarde said the amount of powder was "minute" and was barely enough to test.

The water building and City Hall both opened again about 12:30 p.m. No one in either building came into contact with the yellow powder, the release says.

Velarde declined to criticize the employee who first reported the powder and commended the person for following the city's emergency plan.

"It was a great exercise," he said. "It will give us a chance to work on things."