At least two people have died in forest fires in the southern Brazilian state of Sao Paulo, local authorities said. More than 40 cities have been placed on maximum alert.

The fires are raging in the area outside Sao Paulo, one of Latin America’s most populous cities with more than 11 million people. At least 7,300 government employees and volunteers have been deployed across the state “to contain the advance and extinguish these fires,” said Tarcisio de Freitas, the state’s governor.

De Freitas warned that strong winds could fan the flames. The government said two factory workers were killed Friday while trying to put out a fire in the town of Orubas. Further details were not available.

The region is experiencing its worst forest fires in decades. They are always common in the region during the dry season, but they are also caused by farmers clearing parts of the forest. For example, to make it suitable for raising cattle or growing soybeans, which are sold as animal feed, among other things.

The Brazilian Minister of Environment announced after his meeting with President Lula that the Federal Police had begun an investigation to determine the causes of the fires.

“So far we have not detected any fire caused by lightning, which means there are people who are setting fires,” Lula said in a statement. Governor de Freitas said yesterday that two people suspected of setting the fires had been arrested.