A fire at a fuel storage facility run by Ultracargo near Santos, Brazil’s largest port, spread further on Saturday as it entered its third day despite firefighters’ efforts to contain the flames. The fire spread to a nearby tank filled with gasoline, according to a statement from Ultracargo, which is owned by Grupo Ultra. There were no casualties, it said. Six tanks have been hit so far and four of them were still burning. Explosions were heard at the facility on Thursday morning, swiftly turning into a blaze that sent a thick column of black smoke into the air. Environmental authorities were monitoring the air quality in nearby cities affected by the smoke. Firefighters said there was little they could do to extinguish the flames before all the fuel was consumed. Instead, they focused on dousing nearby tanks to keep the fire from spreading. “The battle is very difficult,” they said on their official Twitter account. Two other tanks are near those currently affected - one is empty and the other filled with ethanol, Ultracargo said. Traffic was diverted around the site of the blaze, blocking one of the roads to the port. Trucks carrying soybeans and other commodities were still able to access the port via a second entrance, a spokeswoman for the local CET traffic engineering company said on Friday.