Epic flooding in the Southeast Indian state of Tamil Nadu has killed 296 people, according to The Indian Express, citing media reports.

Chennai, the state capital, endured the worst flooding, triggered by more than 50 inches of rain in November and December, according to a World Meteorological Organization release. The ancient city of 9 million people became an island.

A BBC News report says the flooding has receded in most parts of the state and cleanup is under way in Chennai. Some roads are still flooded (see a crowd-sourced map of flooded streets here). There is garbage on the streets, and sewage has entered homes, according to the BBC. The city has suffered extensive infrastructure damage as well as damage to thousands of homes. The Chief Minister of Tamil Nadu has requested the event be declared a National Calamity.

Individuals and nonprofits are helping with relief efforts.

Major floods like this one can pose serious health hazards from contaminated water and food, wet electric appliances, an increase in disease-carrying mosquitoes and other threats, so it’s critical to take certain precautions.

Do’s and don’ts

The Tamil Nadu government and India’s National Disaster Management Authority offer these do’s and don’ts to help you stay safe.

Do’s include:

  • Raise furniture and electrical appliances by placing them on beds and tables.
  • Put sandbags in the toilet bowl and cover all drain holes to prevent sewage back flow.
  • Use bleaching powder and lime to disinfect your home.
  • Eat freshly cooked or dry food, and always keep your food covered.
  • Boil water or use chlorine tablets to purify water before drinking as advised by the Health Department.
  • After the flood recedes, watch out for broken electric poles, damaged bridges, broken glass, sharp objects and debris. (Stay on dry ground when possible.)
  • Use mosquito nets and repellents to prevent malaria.
  • Keep your mobile phones charged.
  • Listen to the radio or watch TV for the latest weather bulletin and flood warnings.
  • Keep strong ropes, a lantern, battery-operated torches and extra batteries ready.
  • Keep your first aid kit ready with extra medication for snake bites and diarrhea.
  • Keep umbrellas and bamboo sticks with you for protection from snakes.
  • Stay in touch with local officials, and follow instructions if asked to evacuate.
  • If you’re being evacuated, pack some clothing, essential medication, valuables and important documents in waterproof bags to be taken to a safe shelter. Turn off power and gas connections before leaving the house.
  • Keep cattle untied to ensure their safety.

Don’ts include:

  • Don’t enter flood waters. If you need to enter them, wear suitable footwear.
  • Don’t walk through moving water. If you have to walk in water, walk where it is not moving. (Six inches of swiftly moving water can sweep you off your feet, according to the American Red Cross.) Use a stick to check the firmness of the ground in front of you.
  • Don’t get near electric poles or fallen power lines to avoid electrocution.
  • Don’t get near sewage lines, gutters, drains, culverts, etc.
  • Don’t allow children to have empty stomachs.
  • Don’t leave the safe shelter until local officials declare that conditions are back to normal.
  • Don’t allow children to play in or near flood waters.
  • Don’t use any damaged electric goods. Get them checked by an electrician before using them.
  • Don’t use toilets or tap water if water lines or sewage pipes are damaged.
  • Don’t eat food that has been in flood waters.
  • Don’t drive into flooded areas. If flood waters rise around your car, abandon it and move to higher ground if you can do so safely. Less than 2 feet of water can sweep away most cars, according to the American Red Cross.

More on water safety

According to Chennai Metro Water, during the ongoing monsoon, Chennai Metro Water is supplying super chlorinated water that is safe to drink. It also advises:

  • If rainwater has entered into the underground tank, empty the tank and clean it with bleaching powder.
  • Keep all water containers closed.
  • Add bleaching powder to water in the overhead tanks. Use 2 tablespoons of powder for every 1000 liters of water.

More on food safety

According to UL, if power is lost, an unopened refrigerator will maintain a safe temperature for perishable foods for about four hours. If the food looks or smells bad, discard it, but otherwise, follow these tips when deciding what to keep.

For perishable foods such as meat, poultry, fish, milk and leftovers, use a clean and sanitized meat thermometer, if you have one, to measure the internal temperature. Foods that have sustained an internal temperature of more than 40°F (4.4°C) for longer than two hours must be thrown out. It’s dangerous even if you cook or reheat it.

To help determine which commonly refrigerated foods are considered perishable, use this guide from the U.S. Department of Health and Human Services.

Watch out for electrical hazards

UL warns that as communities begin to clean up after a flood, electrical hazards may be hidden.

Do not turn on electrical items or touch circuit breakers if you are wet, and unplug wet appliances until they have been checked by a qualified electrician or electrical inspector. Even products such as lamps and vacuum cleaners should not be used until they are completely dried out and no longer pose the danger of electrical shock, according to UL.

It is important to follow safety tips, such as not flipping on a switch or plugging in an appliance until an electrician tells you it’s safe, according to UL. If you have experienced significant flooding, you will need a professional technician to check the wiring in your home for shock and fire hazards. This could include anything from circuit breakers to outlets and light switches.

A word on carbon monoxide

If your power is out, don’t use a portable generator indoors. Generators produce odorless carbon monoxide, which can be fatal if the fumes build up inside the home according to UL. Use it outside and place it away from windows and doors.

CO poisoning can cause flu-like symptoms such as headaches, chest tightness, dizziness, fatigue, confusion and breathing difficulties. The victim’s skin may appear pink or red. If anyone in the home is experiencing symptoms of CO poisoning, immediately evacuate the house and seek medical attention.

Todd B. Bates, a finalist for the 2010 Pulitzer Prize in Public Service, is a freelance environmental, health and science writer and investigative reporter. He was a staff reporter for New Jersey newspapers for nearly 35 years. His most recent assignment was covering the environment and severe weather as a member of the Investigations Team at the Asbury Park Press.