Pools of standing or stagnant water become 

breeding grounds for mosquitoes, increasing 

the risk of encephalitis, West Nile virus or other 

mosquito-borne diseases. The presence of wild 

animals in populated areas increases the risk of 

diseases caused by animal bites (e.g., rabies) as 

well as diseases carried by fleas and ticks.

Protect Yourself

After a major flood, it is often difficult to maintain 

good hygiene during cleanup operations. To 

avoid waterborne disease, it is important to wash 

your hands with soap and clean, running water, 

especially before work breaks, meal breaks, and 

at the end of the work shift. Employees should 

assume that any water in flooded or surrounding 

areas is not safe unless the local or state authorities 

have specifically declared it to be safe. If no safe 

water supply is available for washing, use bottled 

water, water that has been boiled for at least 

10 minutes or chemically disinfected water. (To 

disinfect water, use 5 drops of liquid household 

bleach to each gallon of water and let it sit for at 

least 30 minutes for disinfection to be completed.) 

Water storage containers should be rinsed 

periodically with a household bleach solution.

If water is suspected of being contaminated with 

hazardous chemicals, cleanup workers may need to 

wear special chemical resistant outer clothing and 

protective goggles. Before entering a contaminated 

area that has been flooded, you should don plastic 

or rubber gloves, boots, and other protective 

clothing needed to avoid contact with floodwater.

Floodwater

Floodwater often contains infectious organisms, 

including intestinal bacteria such as E. coli, 

Salmonella, and Shigella; Hepatitis A Virus; and 

agents of typhoid, paratyphoid and tetanus. The 

signs and symptoms experienced by the victims 

of waterborne microorganisms are similar, even 

though they are caused by different pathogens. 

These symptoms include nausea, vomiting, 

diarrhea, abdominal cramps, muscle aches, 

and fever. Most cases of sickness associated 

with flood conditions are brought about by 

ingesting contaminated food or water. Tetanus, 

however, can be acquired from contaminated 

soil or water entering broken areas of the skin, 

such as cuts, abrasions, or puncture wounds. 

Tetanus is an infectious disease that affects 

the nervous system and causes severe muscle 

spasms, known as lockjaw. The symptoms may 

appear weeks after exposure and may begin 

as a headache, but later develop into difficulty 

swallowing or opening the jaw. 

Floodwaters also may be contaminated by 

agricultural or industrial chemicals or by 

hazardous agents present at flooded hazardous 

waste sites. Flood cleanup crew members who 

must work near flooded industrial sites also 

may be exposed to chemically contaminated 

floodwater. Although different chemicals cause 

different health effects, the signs and symptoms 

most frequently associated with chemical 

poisoning are headaches, skin rashes, dizziness, 

nausea, excitability, weakness, and fatigue. 

Flood Cleanup

Flooding can cause the disruption of water purification and sewage disposal 

systems, overflowing of toxic waste sites, and dislodging of chemicals previously 

stored above ground. Although most floods do not cause serious outbreaks of 

infectious disease or chemical poisonings, they can cause sickness in employees 

and others who come in contact with contaminated floodwater. In addition, flooded 

areas may contain electrical or fire hazards connected with downed power lines.

FactSheet
Decrease the risk of mosquito and other insect 

bites by wearing long-sleeved shirts, long pants, 

and by using insect repellants. Wash your hands 

with soap and water that has been boiled or 

disinfected before preparing or eating foods, after 

using the bathroom, after participating in flood 

cleanup activities, and after handling articles 

contaminated by floodwater. In addition, children 

should not be allowed to play in floodwater 

or with toys that have been in contact with 

floodwater. Toys should be disinfected.

What to Do If Symptoms Develop

If a cleanup worker experiences any of the signs 

or symptoms listed above, appropriate first-aid 

treatment and medical advice should be sought. 

If the skin is broken, particularly with a puncture 

wound or a wound that comes into contact with 

potentially contaminated material, a tetanus 

vaccination may be needed if it has been five years 

or more since the individual’s last tetanus shot. 

Tips to Remember

• Before working in flooded areas, be sure that 

your tetanus shot is current (given within the 

last 10 years). Wounds that are associated with 

a flood should be evaluated for risk; a physician 

may recommend a tetanus immunization.

• Consider all water unsafe until local 

authorities announce that the public water 

supply is safe.

• Do not use contaminated water to wash and 

prepare food, brush your teeth, wash dishes, 

or make ice.

• Keep an adequate supply of safe water 

available for washing and potable water 

for drinking.

• Be alert for chemically contaminated floodwater at industrial sites.

• Use extreme caution with potential chemical 

and electric hazards, which have great potential 

for fires and explosions. Floods have the 

strength to move and/or bury hazardous waste 

and chemical containers far from their normal 

storage places, creating a risk for those who 

come into contact with them. Any chemical 

hazards, such as a propane tank, should be 

handled by the fire department or police.

• If the safety of a food or beverage is 

questionable, throw it out. 

• Seek immediate medical care for all 

animal bites.

DSTM FS-3471 10/2005

This is one in a series of informational fact sheets highlighting OSHA programs, policies or 

standards. It does not impose any new compliance requirements. For a comprehensive list of 

compliance requirements of OSHA standards or regulations, refer to Title 29 of the Code of Federal 

Regulations. This information will be made available to sensory-impaired individuals upon request. 

The voice phone is (202) 693-1999; teletypewriter (TTY) number: (877) 889-5627.