Irma is hurtling toward two Florida nuclear power plants

As Florida prepares for one of the largest mass evacuations in U.S. history in the face of Hurricane Irma, two nuclear power plants are bracing for impact.

Officials at Florida Power & Light (FPL) are monitoring two facilities housing their four nuclear reactors along the state’s coast, which could shut down if Irma makes landfall as expected this weekend in the Sunshine State. Combined, the reactors provide power for nearly 2 million homes.

Irma, one of the strongest ever recorded storms in the Atlantic, rolled through the Caribbean Wednesday and reportedly caused at least 10 deaths. A spokesperson at FPL could not comment on the current status of the facilities Thursday as they prepare to meet the storm.

As of Wednesday afternoon, though, the facilities were still open, but that may not continue.

“If we anticipate there will be direct impacts on either facility, we’ll shut down the units,” FPL spokesman Peter Robbins told the Miami Herald.

The facilities, which sit along Biscayne Bay and off the Florida coast near West Palm Beach, are designed to withstand hurricane conditions. The reactors at Turkey Point are encased in six feet of steel-reinforced concrete, sit 20 feet above sea level, and are supported with backup generators and extra fuel. Those at the St. Lucie plant feature equal protections.

Still, they’re not impervious to harm. Hurricane Andrew, which, like Irma, was a Category 5 storm, hammered Turkey Point in 1992, causing $90 million in damage, though its reactors weren’t damaged.

“It handled Andrew as it was designed to,” Robbins, the FPL spokesman, told the Miami Herald. “It’s one of the safest and most robust structures in the state, if not the country.”

These facilities aren’t the first industrial sites to face risks during this brutal storm season. Hurricane Harvey caused Texas oil facilities to shut down and release harmful toxins into the air. Even after initial reassurances that there was no imminent danger, Harvey also prompted explosions at a chemical plant in Crosby, Texas, sending at least 15 people to the hospital.