Public Health Statement for Boron

Spanish: Boro

CAS#: 7440-42-8

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This Public Health Statement is the summary chapter from the Toxicological Profile for boron. It is one in a series of Public Health Statements about hazardous substances and their health effects. A shorter version, ToxFAQs™, is also available. This information is important because this substance may harm you. The effects of exposure to any hazardous substance depend on the dose, the duration, how you are exposed, personal traits and habits, and whether other chemicals are present. For more information, call the ATSDR Information Center at 1-800-232-4636.

What is boron?

Naturally occurring
Boron is a widely occurring element in minerals found in the earth’s crust. It is the 51st most common element found in the earth’s crust and is found at an average concentration of 8 mg/kg (approximately 0.0008%).

Combines with oxygen to form borates
Boron is found in the environment primarily combined with oxygen in compounds called borates. Common borate compounds include:

  • boric acid
  • sodium tetraborates (also referred to as borax)
  • boron oxide

Used to manufacture industrial and consumer products
Borate-containing minerals are mined and processed to produce borates for several industrial uses in the United States including:

  • glass and ceramics
  • soaps and detergents
  • fire retardants
  • pesticides

What happens to boron when it enters the environment?

Released into air, water, and soil
Boron can be released into air, water, or soil after natural weathering of soils and rocks.

Smaller amounts of boron can be released from:

  • glass manufacturing plants
  • coal-burning power plants
  • copper smelters
  • agricultural fertilizer and pesticide usage.

Is not broken down
Boron cannot be destroyed in the environment. It can only change its form or become attached or separated from particles in soil, sediment, and water.

How might I be exposed to boron?

You can be exposed to boron in food, mainly vegetables and fruits, as boron is an essential element in plants. The average daily intake of boron for adults is 1 milligram.

Boron is widely distributed in surface water and groundwater.

  • the average surface water concentration is about 0.1 mg per liter (mg/L)
  • boron concentrations in groundwater can be as high as 300 mg/L in areas with natural boron-rich deposits
  • concentrations up to 0.4 mg/L have been found in most drinking water samples

Average concentrations of 26 and 33 mg per kilogram (mg/kg) have been reported in soil.

The general public is not likely to be exposed to air contaminated with boron. The average level of boron in air samples is 0.00005 mg boron per cubic meter of air (mg boron/m3).

Workplace air
In workplaces that mine and process borates, boron concentrations in dusty air samples have been reported to range from about 0.5 to 3 mg boron/m3.

Consumer products
Boric acid, anhydrous sodium tetraborate, and sodium tetraborate decahydrate (borax) are found in consumer products such as:

  • laundry detergent
  • pesticides
  • facial creams and cleaners
  • plant foods
  • household cleaners

How can boron enter and leave my body?

Most ingested boron is absorbed
Boron can enter your body when you eat food (fruits and vegetables), drink water containing it, when you breathe borate dust in the air, and when damaged skin comes in contact with it.

Typically leaves your body within 4 days
Most of the boron leaves the body in urine.

Over half of the boron taken by mouth can be found in urine within 24 hours and the other half can be detected in urine for up to 4 days

How can boron affect my health?

Scientists use many tests to protect the public from harmful effects of toxic chemicals and to find ways for treating persons who have been harmed.

The effect of boron on human health depends on how much boron is present, how you are exposed to it, and the length of exposure.

Exposure in air
People working in dusty workplaces where borates are mined and processed have reported irritation of the nose, throat, and eyes. The irritation does not persist for long periods after leaving the dusty area.

Exposure by ingestion
Humans: Exposure to large amounts of boron (about 30 g of boric acid) over short periods of time can affect the stomach, intestines, liver, kidney, and brain and can eventually lead to death.

Animals: Studies of dogs, rats, and mice indicate that the male reproductive organs, especially the testes, are affected if large amounts of boron are ingested for short or long periods of time. The doses that produced these effects in animals are more than 1,800 times higher than the average daily intake of boron in food by adults in the U.S. population.

No evidence of cancer was found in a study in which mice were given boric acid in the diet throughout their lifetime.

How can boron affect children?

This section discusses potential health effects in humans from exposures during the period from conception to maturity at 18 years of age.

Children are likely to have similar
It is likely that children would show the same health effects as adults. We do not know whether children differ in their susceptibility to the effects of boron.

Birth defects
We do not know whether boron causes birth defects in people. Low birth weights, birth defects, and developmental delays have occurred in newborn animals whose mothers were orally exposed to high doses of boron (as boric acid). The doses that produced these effects in pregnant animals are more than 800 times higher than the average daily intake of boron in food by adult women in the U.S. population.

How can families reduce the risk of exposure to boron?

Boron is part of the natural environment and you will have some exposure from foods and drinking water.

Limit children's exposure to pesticides
Pesticides containing boron compounds should be used according to their directions and should be kept away from children.

Store household chemicals out of reach of young children
Always store household chemicals in their original labeled containers out of reach of young children to prevent accidental poisonings. Never store household chemicals in containers children would find attractive to eat or drink from, such as old soda bottles.

Discourage children from eating dirt or putting hands in their mouth while playing with dirt
Children living near waste sites containing boron and boron compounds are likely to be exposed to higher than normal environmental levels of boron through breathing in boron-containing dust, and touching and eating contaminated soil.

Children should be encouraged to wash their hands frequently, especially before eating.

Is there a medical test to determine whether I have been exposed to boron?

Can be measured in blood and urine
Blood and urine can be examined to determine whether excessive exposure to boron has occurred.

The detection of boron in the blood or urine cannot be used to predict the kind of health effects that might develop from that exposure.

What recommendations has the federal government made to protect human health?

The federal government develops regulations and recommendations to protect public health. Regulations can be enforced by law. The EPA, the Occupational Safety and Health Administration (OSHA), and the Food and Drug Administration (FDA) are some federal agencies that develop regulations for toxic substances. Recommendations provide valuable guidelines to protect public health, but cannot be enforced by law. The Agency for Toxic Substances and Disease Registry (ATSDR) and the National Institute for Occupational Safety and Health (NIOSH) are two federal organizations that develop recommendations for toxic substances.

Regulations and recommendations can be expressed as “not-to-exceed” levels, that is, levels of a toxic substance in air, water, soil, or food that do not exceed a critical value that is usually based on levels that affect animals; they are then adjusted to levels that will help protect humans. Sometimes these not-to-exceed levels differ among federal organizations because they used different exposure times (an 8-hour workday or a 24-hour day), different animal studies, or other factors.

Recommendations and regulations are also updated periodically as more information becomes available. For the most current information, check with the federal agency or organization that provides it.

Some regulations and recommendations for boron include the following:

Levels in drinking
The EPA has determined that exposure to boron in drinking water at concentrations of 4 mg/L for one day or 0.9 mg/L for 10 days is not expected to cause any adverse effects in a child.

The EPA has determined that lifetime exposure to 1 mg/L boron is not expected to cause any adverse effects.

Levels in workplace air set by OSHA
OSHA set a legal limit of 15 mg/m3 for boron oxide in air averaged over an 8-hour work day.


Agency for Toxic Substances and Disease Registry (ATSDR). 2010. Toxicological profile for Boron. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

Where can I get more information?

If you have questions or concerns, please contact your community or state health or environmental quality department or:

For more information, contact:
Agency for Toxic Substances and Disease Registry
Division of Toxicology and Human Health Sciences
4770 Buford Highway
Chamblee, GA 30341-3717
Phone: 1-800-CDC-INFO 888-232-6348 (TTY)
Email: Contact CDC-INFO

ATSDR can also tell you the location of occupational and environmental health clinics. These clinics specialize in recognizing, evaluating, and treating illnesses resulting from exposure to hazardous substances.

Page last reviewed: October 25, 2011