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Even the cleanest home can present human health hazards. Problems may be caused by the structure of the house or the materials used to build it. Chemicals found in common household products may be toxic. Household conditions can cause asthma and allergies. Fire, injuries, and insect or animal bites may also threaten your safety and health at home. 

See also: Ammonia Benzene Bisphenol A (BPA) Cadmium Chlorofluorocarbons (CFCs) Ethylene Glycol Formaldehyde Methanol Nanoparticles Natural Gas Nitrogen Oxides Particulate Matter Polybrominated Diphenyl Ethers (PBDEs) Polyvinyl Chloride (PVC) Solvents Styrene Endocrine Disruptors Lead Carbon Monoxide Volatile Organic Compounds (VOCs) Phthalates Acetone Radon Pesticides Perfluorooctanoic Acid (PFOA)

What are they?

An allergy is a reaction by your immune system to something in your environment. People who have allergies often are sensitive to more than one thing. Substances that often cause allergies include:

  • Dust mites
  • Food
  • Insect stings
  • Medicines
  • Mold spores
  • Pet dander
  • Pollen

Why are they a concern?

Allergies can cause symptoms such as a runny nose, sneezing, itching, rashes, swelling, or asthma. Untreated allergies can cause significant health problems and affect your quality of life. 

Doctors use skin and blood tests to diagnose allergies. Treatments include medicines, allergy shots, and avoiding the substances that cause the reactions.

What pollutants are of greatest concern and who is at risk?

Allergies can range from minor to severe. Anaphylaxis is a serious, life-threatening allergic reaction that requires immediate medical attention. Anaphylactic reactions typically happen in response to certain foods, insect stings, medications, and latex. Symptoms include a red, itchy rash, shortness of breath, and throat tightness. Severe cases may cause a drop in blood pressure, which can result in a loss of consciousness and shock. 

It is unclear why only some substances trigger allergies, and why only some people have allergic reactions. We do know that a family history of allergies puts you at risk for developing allergies.

What are they?

Gardening is a popular way to enjoy the outdoors, grow plants and food, and beautify a yard. Many homes are decorated with houseplants that add color, warmth, and natural life to rooms. 

Why are they a concern?

Though they are common in our lives, gardens and houseplants pose several health risks:

  • Indoors and outdoors, touching or eating poisonous plants can cause allergic reactions, skin rashes, illnesses, and even death if ingested in high quantities. 
  • Products used on lawns and in gardens to prevent or kill pests and weeds can also harm people.
  • Some garden pests sting or bite, and some can damage buildings. 

What pollutants are of greatest concern and who is at risk?

Some of the most common and familiar poisonous plants are poison ivy, poison oak, and poison sumac, which cause allergic skin reactions. The most deadly poisonous plant is the castor bean plant, which contains a highly toxic poison called ricin. Even a very small dose of ricin may be lethal. 
Other poisonous plants and trees include: 

  • Chinaberry
  • Elephant ear
  • Foxglove
  • Golden chain
  • Jerusalem cherry
  • Laurel
  • Mistletoe
  • Monkshood
  • Nightshade
  • Oleander
  • Philodendron
  • Water and poison hemlock

Touching or ingesting pesticides or herbicides may also cause harm. Some pesticides are known to cause cancer and birth defects, affect the nervous system, and irritate the skin and eyes. 

Anyone touching or eating poisonous plants is at risk for harm.

National Library of Medicine Resources and Databases
Additional Resources

What is it?

Homes are built with materials such as lumber, brick, concrete, insulation, glass, and paint. Building codes governing which materials may be used to build homes help protect public health, safety, and the environment.

Why is it a concern?

Home construction, roofing, and insulation materials may contain harmful chemicals. 

What pollutants are of greatest concern and who is at risk?

Older homes may have materials that contain asbestos or lead. Asbestos can be found in insulation, wiring, and roof or siding shingles. Lead is sometimes found in old plumbing and paint. During the 1970s and 1980s, legislation regulated the use of asbestos in the U.S. Lead-based paints were banned for use in housing in 1978.


Radon is a cancer-causing radioactive gas that forms naturally in rocks and soil and can enter a home through cracks in the home’s foundation. Radon is colorless and odorless, but can contaminate the air.


Construction workers and others who work on or near construction sites, as well as home owners and residents living in homes undergoing renovation, may be at risk. 

What are they?

Household chemicals are commonly found in consumer products we use to clean, control pests, and maintain general hygiene. These products help us keep healthy conditions in the home.

Why are they a concern?

You come into contact with chemicals at home every day. Although some chemical exposures are safe, others are not. For you to become sick, a certain amount of a harmful chemical must enter your body. Harmful chemicals can get into your body if you breathe, eat, or drink them or if they are absorbed through your skin.

Cleaning supplies containing toxic substances include:

  • Aerosol spray products, including health, beauty, and cleaning products
  • Air fresheners
  • All-purpose cleaners
  • Antibacterial cleaners
  • Chlorine bleach
  • Dishwashing liquid
  • Drain cleaners
  • Furniture and floor polish
  • Laundry detergent
  • Mold and mildew removers
  • Oven cleaners
  • Rug and upholstery cleaners
  • Toilet bowl cleaners
  • Window and glass cleaner

Other potentially harmful household products include: 

Depending on the ingredients used, household chemical products can:

  • Be highly poisonous if swallowed
  • Cause headaches 
  • Irritate the skin, eyes, nose, and throat
  • Release low levels of cancer-causing chemicals
  • Trigger asthma symptoms and respiratory illness

What pollutants are of greatest concern and who is at risk?

Some household chemical hazards include:

If not properly stored or used, household chemical products can cause health problems for you or your children. Fortunately, you can limit your risk. Read all labels and follow instructions when using and storing these products.

What are they?

Molds are tiny organisms that help break down plant and animal matter. Outdoors, molds can be found in shady, damp areas, or places where leaves or other vegetation are decomposing. Indoors, molds can grow on almost any surface where there is moisture, oxygen, and organic material. When molds are disturbed, they release tiny cells called spores into the surrounding air.

Why are they a concern?

Molds can contaminate indoor air and cause health problems. Inhaling or touching mold or mold spores may cause allergic reactions or asthma attacks in sensitive people. Molds can cause fungal infections. In addition, mold exposure may irritate your eyes, skin, nose, throat, and lungs. 

What pollutants are of greatest concern and who is at risk?

The most common indoor molds are:
•    Alternaria
•    Aspergillus
•    Cladosporium
•    Penicillium
•    Stachybotrys chartarum (also known as black mold)
After contact with certain molds, individuals with chronic respiratory disease may have difficulty breathing, and people who have an immunodeficiency may be at increased risk for lung infection. Mold exposure during the first year of life may increase the risk of childhood asthma.

National Library of Medicine Resources and Databases
Additional Resources
  • Mold (National Institute of Environmental Health Sciences)

What are they?

Pets are domestic or tamed animals kept for companionship or pleasure. For many of us, pets are part of the family. 

Why are they a concern?

Household and farm pets can cause mild health problems in humans, such as allergies, or even carry and transmit diseases. Proper hygiene and handwashing around pets can help to eliminate some of these risks.

What pollutants are of greatest concern and who is at risk?

Common household pets may transmit several diseases to humans, including:

  • Cat-scratch disease, caused when cats get bacteria from fleas
  • Lyme disease, caused by bacteria transmitted by ticks
  • Parasitic infection from hookworms, ringworms, roundworms, and tapeworms
  • Psittacosis, an infectious disease transmitted by birds
  • Rabies, a deadly virus spread to people from the saliva of infected animals
  • Rat-bite fever, a bacterial illness transmitted by infected rodents
  • Rocky Mountain spotted fever, a disease transmitted by ticks
  • Salmonella, a bacterial infection
  • Toxoplasmosis, a parasitic disease transmitted through cat feces

Pets that have been treated with pesticides or wear flea collars can expose humans to health risks. Some pets’ dead skin flakes, urine, feces, saliva, and hair can trigger asthma.


Farm animals can transmit rabies, ringworm, salmonella, West Nile virus, and Q fever, a bacterial disease associated with cattle, goats, and sheep. 


Some people are more likely than others to get diseases from pets, including: 

  • Infants and children under the age of five
  • People undergoing cancer treatment
  • People with an immunodeficiency 
  • People with organ transplants
  • Pregnant women
  • The elderly
National Library of Medicine Resources and Databases
Additional Resources

Reduce your risk

  • Do you use well water?
  • Do you smoke, or live with someone who smokes?
  • Do you use household chemical products?
  • Do you live in a home with water leakage?
  • Do you live in a home undergoing renovation?
  • Do you properly ventilate your home? 
  • Do you have smoke and carbon monoxide detectors?
  • Do you live in a home with asbestos or lead paint?
  • Routinely test well water for chemical contamination.
  • If your well water has high levels of chemicals, contact your local or state health agency or the Centers for Disease Control and Prevention for information on how to reduce your exposure to these chemicals.
  • Test for and remediate high levels of radon in your basement. 
  • Maintain good indoor air quality at home.
  • If you smoke, quit, and encourage your friends and loved ones to quit. Avoid second-hand smoke.
  • Use household chemical products safely: 
    • Keep products in their original containers.
    • Properly ventilate when using chemical products. 
    • Read all labels on chemical products before you buy and use them. 
    • Never mix bleach or any bleach-containing product with any cleaner containing ammonia.
  • Install smoke and carbon monoxide detectors in your home, and change their batteries regularly.
  • Resolve any water leakage to avoid mold, mildew, and pests.
  • Hire qualified experts for home renovations and repairs, and for asbestos and lead remediation.
  • Know the symptoms of poisoning and how to contact your local poison control center.
  • Keep children away from home construction projects.
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