Not only is it incredibly unsafe it is also illegal for an employer to allow workers in the space without the proper protective gear.
Asbestos in the air in any amount is dangerous. The fibers go into your lungs and latch on forever.
The Occupational Safety and Health Administration would shut the place down and fine the heck (to put it mildly) out of the people in charge there.
Your boyfriend can and should refuse to work in there without a respirator designed to filter out asbestos. If his boss tries to fire him for it, sue him. Contact OSHA they have helped some people with their cases.
