Firefighters battled a fire at a solvents factory in Lavrion, southeast of Athens, late yesterday as a black toxic cloud covered the area, prompting authorities to instruct residents to stay indoors. The fire, which broke out at about 10 a.m., spread quickly to five chemical tanks at the Hima factory as hundreds of firefighters worked to keep the blaze from spreading to nearby units. The factory’s 20 workers managed to escape unharmed, according to authorities. Due to the threat posed by the blaze, all firefighters in the Attica region were on standby late yesterday because the fire was still not under control. More than 180 firefighters using 51 trucks were involved in the operation, which involved three helicopters and four water-dropping planes. Authorities said that extremely high temperatures and multiple explosions made it very difficult for the fire service to extinguish the blaze. One source said the firefighters on land will be able to manage the flames more efficiently after the chemicals have burned off and temperatures cool. Authorities advised locals to stay indoors, shut their windows and travel in the area only while wearing masks or some other covering over their faces. Some 10,000 protective masks were sent to the Lavrion medical clinic. By By last night, authorities had not decided whether to evacuate the area. «This is an extremely dangerous situation, especially for vulnerable groups, as these substances are particularly toxic,» said Michalis Petrakis, research director of the Institute of Environmental Research and Sustainable Development (IERSD) at the National Observatory of Athens.