Over 4.3 million customers in Texas are in the dark Tuesday morning as snow and freezing temperatures continue to pummel the state.

Some power outages also extend to Kentucky, West Virginia, Virginia, Louisiana, Mississippi, Ohio, Tennessee, Arkansas, North Carolina, Oregon, New York, Illinois, Missouri, Kansas, Oklahoma, South Dakota, Nebraska and New Mexico.

Here are safety tips to keep in mind:

Ahead of an outage, federal emergency officials advise installing carbon monoxide detectors and stocking up on batteries.

During a power outage, it is important to be mindful of carbon monoxide poisoning. The Texas Medical Center in Houston reported 60 cases of carbon monoxide poisoning on Monday.

Never use a gas stovetop or oven to heat your home, and only use generators, camp stoves or charcoal grills when you are outdoors and at least 20 feet away from windows, FEMA officials said.

Keep freezers and refrigerators closed during the power outage, instead using food that doesn’t require refrigeration or coolers with ice. The fridge will keep food cold for about four hours while a freezer will maintain the temperature for about 48 hours, officials said.

FEMA officials recommend storing a thermometer in the fridge and freezer; once power is restored, throw out food if the temperature is 40 degrees or higher.

If the power is out for more than one day, throw out any medication that should be refrigerated, unless the label says otherwise, FEMA officials said.

While trying to stay warm, officials in Bexar County, Texas, recommend closing the blinds to keep in some heat, closing off rooms to avoid wasting heat and stuffing towels or tags in cracks under doors.