[originaltext]　　(3) A chemical explosion at a cargo warehouse in Brazil has spr

　　(3) A chemical explosion at a cargo warehouse in Brazil has spread a plume of toxic gas over the country’s biggest port, Santos.
　　The company owners said the containers were full of acid and a disinfectant (消毒剂) which they think came into contact with rainwater, causing a reaction. The cargo terminal and nearby homes have been evacuated and residents have been asked to stay inside. Several people have been taken to hospital with breathing difficulties. (4) The container terminal was operated by Localfrio, a logistics company, in Guaruja, an area on the eastern side of Santos. A spokeswoman for the company, which exports chemicals used for refrigeration and general cargo, said the containers were filled with chloric acid and sodium dichloroisocyanurate—a cleaning and disinfectant agent. Local Mayor Mario Antonieta de Brito asked people to stay out of the rain which could "contain chemical elements that can burn the skin. "
　　3. What is the news report mainly about?
　　4. What do we learn about Localfrio from the news report?