About 20 employees in the county's Department of Social Services office in Salinas have been evacuated since September because of mould found inside the building's walls.

Ross Richards, Monterey County's facilities manager, said inspectors did a walk-through of the office, in the Quadrangle Building at 1000 S. Main St., after employees complained that they felt sick. They found leaks along a wall that leads down to the basement.

The leaks were caused by a landscaping planter adjacent to the wall, Richards said.

Tests showed that the air was clean, but samples from inside the wall showed signs of Stachybotrys chartarum, a greenish-black mould that grows on material with a high cellulose and low nitrogen content. The mould grows when moisture from water damage, excessive humidity, water leaks, condensation, water infiltration or flooding gathers on the surface.

Stachybotrys chartarum may cause health symptoms that are nonspecific, but there is no test that proves an association between it and particular health symptoms, according to the Centers for Disease Control and Prevention.

The county moved out employees last month, soon after the leaks were discovered. Health officials then tested the area inside the wall as well as air in the office.

"As soon as we found out there was a problem, we immediately started mitigating the problem to protect our county employees," Richards said, "even though it's not our building."

The evacuation, on Sept. 11, caused minimal disruption to the department's operations, although emergency distribution of food stamps was stopped for a couple of hours, said Elliott Robinson of the Social Services Department. Only a few employees worked in the small building which was sealed off.

"In the macro-scale of things, there was no disruption," he said. "The department was very concerned about the safety of the staff."

Richards said if the mould had not been disturbed, the air would have been healthy enough to work in. But as the department was talking to a consulting firm about the office's safety conditions, they learned that the building's landlord, Triad Property Management, had torn down the mould-laden wall.

The disturbance forced the county to seal off the office occupied by Social Services to prevent further contamination. Health officials are also conducting more tests.

The management company did not return a phone call Monday requesting comment.

The Social Services Department will continue to work in other offices within the Quadrangle. There are no plans to re-open the old offices, Robinson said.