With more than 20 percent of its staff housed in leased facilities, the Lawrence Berkeley National Laboratory in Berkeley, Calif., is looking for a second campus.

The U.S. Department of Energy facility, operated by the University of California, has about 1.8 million square feet of space on 200 acres near the university campus. But as the lab has grown, many workers are situated in Emeryville, Walnut Creek, Oakland and West Berkeley. Consolidating off-site employees on a single campus would enable researchers to interact more directly, the lab says.

To anticipate future growth, officials say a second site would have to be expandable to accommodate as much as 2 million gross square feet. It also would have to be no more than 20 minutes away from the main lab site. Lab officials say a second site could be ready by 2015.