Smoke Stack

NIEHS provides information about chemicals or factors in the environment to which humans are exposed that may cause adverse health effects.

  • Acrylamide

    Acrylamide is a chemical widely used during the manufacturing of paper, dye, and other industrial products. It can also be formed when certain foods are cooked at high temperatures.

  • Air Pollution and Your Health

    Air pollution is a familiar environmental health hazard. We know what we’re looking at when brown haze settles over a city, exhaust billows across a busy highway, or a plume rises from a smokestack. Some air pollution is not seen, but its pungent smell alerts you.

  • Algal Blooms

    Algae are always in natural bodies of water like oceans, lakes, and rivers, and a few types produce toxins. A harmful algal bloom (HAB) occurs when toxin-producing algae grow excessively in a body of water.

  • Allergens

    Information on allergens, asthma, and pulmonary research performed at NIEHS | Additional resources for managing allergies

  • Aloe Vera

    Aloe is a succulent plant widely used in alternative medicine. There are at least 420 different plant species of Aloe. Aloe vera specifically refers to the Aloe barbadensis Miller plant, which is the most common form used in Aloe-based products.

  • Arsenic

    Arsenic is a naturally occurring element that is widely distributed in the Earth’s crust. It is found in water, air, food, and soil. Exposure to arsenic affects human health.

  • Bisphenol A (BPA)

    Bisphenol A (BPA) is a chemical produced in large quantities for use primarily in the production of polycarbonate plastics and epoxy resins. NIEHS and NTP support research to better understand potential health effects of exposure to BPA.

  • Cell Phone Radio Frequency Radiation

    The National Toxicology Program, headquartered at NIEHS, conducted studies to help us understand potential health hazards, including cancer risk, from exposure to radio frequency radiation like that used in 2G and 3G cell phones.

  • Climate Change

    Climate change is the result of the buildup of greenhouse gases in the atmosphere, primarily from the burning of fossil fuels for energy and other human activities. These gases, such as carbon dioxide and methane, warm and alter the global climate, which causes environmental changes to occur that can harm people's health and well-being.

  • Cosmetics and Your Health

    Cosmetics and personal care products contain a mix of chemicals. Researchers are working to better understand if any affect human health. Some of the chemicals are classified as endocrine disrupting, which means they may interfere with the body’s hormones and cause adverse health effects.

  • Dioxins

    Dioxins are mainly byproducts of industrial practices. They are produced through a variety of incineration processes, including improper municipal waste incineration and burning of trash, and can be released into the air during natural processes, such as forest fires and volcanoes. Almost every living creature has been exposed to dioxins or dioxin-like compounds (DLCs).

  • Dust Mites and Cockroaches

    Dust mites are microscopic, insect-like pests that commonly live in house dust. They feed on flakes of dead skin, or dander, that are shed by people and pets. Cockroaches are another source of indoor allergens. Researchers have found a link between the presence of cockroaches and an increase in the severity of asthma symptoms.

  • Electric & Magnetic Fields

    Electric and magnetic fields (EMFs) are invisible areas of energy, often called radiation, that are associated with the use of electrical power and various forms of natural and man-made lighting. Learn the difference between ionizing and non-ionizing radiation, the electromagnetic spectrum, and how EMFs may affect your health.

  • Endocrine Disruptors

    Endocrine disruptors are natural or man-made chemicals that may mimic or interfere with the body’s hormones, known as the endocrine system. These chemicals are linked with many health problems in both wildlife and people.

  • Essential Oils

    Essential oils are concentrated plant extracts that retain the natural smell and flavor of their source. Some essential oils and their components show hormonal activity and could affect the endocrine system.

  • Flame Retardants

    Flame retardants are chemicals that are applied to materials to prevent the start or slow the growth of fire. Some of these chemicals are associated with adverse health effects in animals and humans.

  • Formaldehyde

    Formaldehyde is a colorless, flammable, strong-smelling chemical widely used to make home building products. Most formaldehyde produced in the United States is for the manufacture of resins, such as urea-formaldehyde, used to make the adhesives for pressed wood products, such as particleboard, furniture, paneling, cabinets, and other products.

  • Hazardous Material/Waste

    Hazardous wastes are discarded materials with properties that make them potentially harmful to human health or the environment.

  • Hexavalent Chromium

    Hexavalent chromium is a form of the metallic element chromium. Chromium is a naturally occurring element found in rocks, animals, plants, soil, and volcanic dust and gases. It comes in several different forms, including trivalent chromium and hexavalent chromium.

  • Hydraulic Fracturing & Health

    Hydraulic fracturing, or fracking, is a method used to extract natural gas and oil from deep rock formations known as shale. Using this method, drilling operators force water, sand, and a mix of chemicals into horizontally drilled wells, causing the shale to crack and release natural gas or oil.

  • Indoor Air Quality

    We tend to think of air pollution as a risk faced outside, but the air we breathe indoors can also be polluted.

  • Lead

    Lead, a metal found throughout the earth, has been used in a variety of products including gasoline, paint, plumbing pipes, ceramics, solders, batteries, and even cosmetics. It remains a significant public health concern for some children because of persistent lead hazards in the environment.

  • Mercury

    Mercury is a metal that is toxic to living organisms. It exists in several forms, some of which occur naturally in the environment. Metallic or elemental mercury — an odorless, shiny, silver-white liquid — is commonly used in thermometers, barometers and fluorescent light bulbs. Metallic mercury is extremely dangerous with a few drops generating enough fumes to contaminate the air in a room. Furthermore, skin contact with the metal results in the absorption of mercury into the blood stream and potential health problems.

  • Mold

    A microorganism and type of fungus, molds are part of the natural environment and can be found everywhere, outside and indoors. Health-related reactions in people depend on mold type, the amount and duration of exposure, and individual characteristics.

  • Nanomaterials

    Nanomaterials, natural and human made, are characterized by size, measured in nanometers. A nanometer is one millionth of a millimeter - about 100,000 times smaller than the diameter of a single hair. NIEHS is working to understand any potential risks associated with exposure to these materials.

  • Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS)

    Per- and polyfluoroalkyl substances (PFAS) are a large, complex group of synthetic chemicals that have been used in consumer products around the world since about the 1950s. They are ingredients in various everyday products. For example, PFAS are used to keep food from sticking to packaging or cookware, make clothes and carpets resistant to stains, and create firefighting foam that is more effective. PFAS molecules have a chain of linked carbon and fluorine atoms. Because the carbon-fluorine bond is one of the strongest, these chemicals do not degrade easily in the environment.

  • Pesticides

    A pesticide is any substance used to kill, repel, or control certain forms of plant or animal life that are considered to be pests. Pesticides include herbicides for destroying weeds and other unwanted vegetation, insecticides for controlling a wide variety of insects, fungicides used to prevent the growth of molds and mildew, disinfectants for preventing the spread of bacteria, and compounds used to control mice and rats.

  • Pet Allergens

    Millions of Americans live with pets despite being allergic to them. Any furry animal may trigger allergy symptoms like sneezing or red, itchy eyes, but most commonly cats and dogs. Pet allergies can also make asthma harder to control.

  • Pollen

    To a tree or a flowering plant, pollen is necessary for life. But to millions of Americans, it is a source of seasonal misery. Pollen, a fine to coarse powdery substance, is created by certain plants as part of their reproduction process. It can appear from trees in the spring, grasses in the summer, and weeds in the fall.

  • Radon

    Radon is a naturally occurring radioactive gas that is colorless and odorless. Radon comes from the natural decay of uranium or thorium, elements found in rocks, soils, and water. Radon breaks down quickly, giving off radioactive particles. When inhaled, these radioactive particles can damage cells that line the lung.

  • Safe Water and Your Health

    Water is essential for life. People depend on safe water for their health and livelihood. But contaminated water leads to millions of deaths and even more illnesses every year.

  • Smoking and Vaping

    The link between cigarette smoke and disease, particularly lung cancer and cardiovascular disease, is well known. Cigarette smoking is the leading cause of preventable death in the United States.

  • Styrene

    Styrene is a colorless, flammable liquid, which has a sweet odor and is highly volatile. Styrene is widely used to make plastics and rubber, which are used to manufacture a variety of products, such as insulation, pipes, automobile parts, printing cartridges, food containers, and carpet backing.

  • Weather Extremes

    Weather extremes can have adverse effects on human health, including concerns from severe heat and cold. Storms and harsh conditions, such as hurricanes and droughts, can create secondary dangers, including floods and wildfires. NIEHS has resources on many types of events and conditions.

Additional Topics

Chemicals (General)

  • Agency for Toxic Substances and Disease Registry (part of CDC) Substance Priority List - In order of priority, this list contains substances most commonly found at facilities on the National Priorities List (NPL) and which are determined to pose the most significant potential threat to human health due to their known or suspected toxicity and potential for human exposure at these NPL sites.
  • The Health Consequences of Involuntary Exposure to Tobacco Smoke - This 2006 Surgeon General’s report updates evidence of the harmful effects of involuntary exposure to tobacco smoke. An accompanying database profiles key epidemiologic findings and enables users to explore the data and studies supporting the conclusions in the report.