REI, the outdoor-sporting-goods retailer, closed three corporate campuses in Washington state after learning of two incidents of potential exposure to the coronavirus, which has businesses grappling with how to make employees feel safe.

The cases met the Centers for Disease Control and Prevention’s definition of “low risk,” according to a company spokesman. That term generally applies to people who were in a room with an infected person but didn’t have close contact. The company will do a deep clean of the offices in Kent, Bellevue and Georgetown before allowing about 1,800 staff and contractors to return.

Employees will work remotely and should stay home if they feel unwell, the spokesman said. The company decided to err on the side of caution, he said.

Washington state has been the epicenter of the outbreak so far in the U.S., with 18 cases and six deaths reported. The deaths have been centered around a nursing home near Seattle in Kirkland, where there are a large number of suspected patients. Health officials said there may be hundreds of infections that haven’t been reported yet in Washington state and potentially more nationwide.

Seattle-based F5 Networks Inc., which helps companies manage data traffic, is reopening its downtown headquarters Tuesday after shuttering the office Monday for a deep clean. An employee who had contact with an infected person has tested negative for the virus, a spokesman said. F5, the only tenant in the building, has about 1,500 workers there. Some schools in the region have closed for similar reasons.

Countries across the world are grappling to contain the spread of the coronavirus, which has claimed the lives of more than 3,000 people. Governments have placed travel restrictions while companies have encouraged employees to work from home and canceled events. Confirmed cases have reached 100 in the U.S.

The moves by REI and F5 are among the more aggressive actions taken by companies in the U.S. Twitter became one of the first American companies Monday to encourage all employees to work from home as a precautionary measure. Many U.S. companies, including AT&T and Citigroup, have restricted international travel, especially to Asia. Others, including Facebook and Google, have postponed or canceled conferences in the U.S., and Facebook joined Twitter Monday in pulling out of South by Southwest. But the full shutdown of campuses is more reminiscent of what companies did in Asia as the virus swept the region.