Arson could be the cause of several wind-driven brush fires that burned on New York’s Long Island over the weekend, injuring two firefighters and sending large smoke plumes into the air, officials said.

The National Weather Service said the weather is cooperating; it is unlikely for fires to spread on Monday, due to calmer weather conditions and a decrease in wind gusts. Suffolk County police are expected to continue an arson investigation into the cause of the fires by using drones and helicopters on Monday.

The brush fires were mostly contained by Sunday morning after burning about 600 acres, injuring two firefighters and prompting a state of emergency Saturday.

The last of four blazes that began in Suffolk County on Saturday has been put out, but Long Island and the Hudson Valley still faced a high fire risk on Sunday, officials said.

Firefighters are working to contain a series of brush fires that swept through New York’s Long Island. High winds caused the fires to jump quickly and send smoke billowing for miles as New York’s Gov.