Some health care facilities in the U.S. lack sufficient supplies of face masks as COVID-19 cases surge across the country and manufacturers work overtime to ramp up production of personal protective equipment. … Makers of so-called N95 masks — regarded as the most effective tool for protection against airborne droplets — are struggling to keep up with demand from hospitals, nursing homes and other health care facilities, as well as businesses in other sectors that now require them to protect workers and the public.