LOS ANGELES — California Gov. Gavin Newsom has declared a state of emergency in response to a fire that has been burning for several days at a cold-storage facility in Los Angeles' Boyle Heights neighborhood.The declaration came as firefighters continued efforts to contain the blaze, which began on Wednesday and has affected air quality in parts of the region.“California is mobilizing to support Los Angeles as firefighters and emergency personnel continue their work to contain this fire and protect surrounding communities,” Newsom said.State officials said they are preparing 5.5 million N95 masks, air purifiers, bottled water and other emergency supplies while expanding air-quality monitoring efforts.Los Angeles Mayor Karen Bass had earlier declared a local emergency, citing concerns over potential health impacts on nearby communities.“We clearly need resources from the state to allow us to take the steps that are needed to make sure that this area is safe,” Bass said.Officials warned that more than 85 million pounds of frozen food stored at the facility could begin decomposing, raising concerns about possible biohazard conditions.Los Angeles Fire Department Chief Jaime Moore said hazardous refrigerants, including ammonia, had already been removed from the site.Fire crews have deployed helicopters capable of dropping up to 3,000 gallons of water at a time and are using gel-based fire retardants to accelerate containment efforts.A smoke advisory remained in effect on Sunday as firefighters continued battling the blaze.