Nearly 30 Prince George’s County churchgoers fell ill after officials say they experienced carbon monoxide poisoning during Sunday service.

According to the Prince George’s County Fire and EMS Department, fire crews joined Montgomery County officials to a house in the 2700 block of Hughes Road. They later figured out the actual incident location was the 3000 block of Buck Lodge Road, behind the original address.

The department said they found between 25 and 30 people inside the church worship service with symptoms of carbon monoxide poisoning, which ranged from vomiting to a headache to dizziness.

After evacuating the building, EMS took 7 people to the hospital, where they were all in stable condition. Four more people took themselves to the hospital the next day.

The department offered these tips to avoid carbon monoxide poisoning:

  • Install at least one battery-powered or hard-wired CO detector on each level of your home and near sleeping areas;
  • Ensure that fuel-burning appliances are properly installed and working according to the manufacturer’s instructions;
  • Do not burn charcoal inside your house, even in the fireplace;
  • Do not use gasoline-powered generators inside of your house;
  • Keep chimneys clear of animal nests, leaves and residue to ensure proper venting; and
  • Do not block or seal shut exhaust flues or ducts for appliances, such as water heaters, ranges and clothes dryers.