CS249955-G

Boron - ToxFAQsTM CAS # 7440-42-8

This fact sheet answers the most frequently asked health questions (FAQs) about boron. For more information, call the CDC 

Information Center at 1-800-232-4636. This fact sheet is one in a series of summaries about hazardous substances and their 

health effects. It is important you understand this information 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.

HIGHLIGHTS: Exposure to boron occurs in the workplace or from using certain 

consumer products. Breathing moderate levels of boron irritates the nose, 

throat, and eyes. Ingestion of large amounts of boron can result in damage to 

the testes, intestines, liver, kidney, and brain. Boron has been found in at least 

164 of 1,689 National Priorities List (NPL) sites identified by the Environmental 

Protection Agency (EPA).

What is boron? 

Boron is a compound that occurs in nature. It is often 

found combined with other substances to form 

compounds called borates. Common borate compounds 

include boric acid, salts of borates, and boron oxide. 

Borates are used mostly to produce glass. They are 

also used in fire retardants, leather tanning industries, 

cosmetics, photographic materials, soaps and cleaners, 

and for high-energy fuel. Some pesticides used for 

cockroach control and some wood preservatives also 

contain borates. 

What happens to boron when it enters 

the environment? 

• Boron is released to the environment from natural 

sources such as oceans, volcanoes, and 

geothermal steam. 

• Boron is also released from industries that use it. 

• 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. 

• Boron is widely distributed in surface water 

and groundwater. 

• The general public is not likely to be exposed to air 

contaminated with boron. 

• Working in borax mining and refining plants and at 

sites where boric acid is manufactured. 

• Using consumer products that contain it, such as 

cosmetics and laundry products. 

How can boron affect my health? 

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 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. 

Studies in animals 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. 

How likely is boron to cause cancer? 

The Department of Health and Human Services, the 

International Agency for Research on Cancer, and the EPA 

have not classified boron as to its human carcinogenicity.

One animal study found no evidence of cancer after 

lifetime exposure to boric acid in food. No human studies 

are available.

Agency for Toxic Substances and Disease Registry

Division of Toxicology and Human Health Sciences 
September 2007 Page 2 of 2

Boron 

CAS # 7440-42-8

How can boron affect children?

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.

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) during pregnancy. 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 risks of 

exposure to boron?

• Pesticides containing boron compounds should be 

used according to their directions and should be kept 

away from 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.

• 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, touching soil, 

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’ve been exposed to boron?

Blood and urine can be examined to determine whether 

excessive exposure to boron has occurred.

These tests can show you were exposed to boron, but 

cannot predict the kind of health effects that might occur.

Has the federal government made 

recommendations to protect 

human health?

The EPA has determined that exposure to boron in 

drinking water at concentrations of 4 ppm for 1 day or 

0.9 ppm for 10 days is not expected to cause any adverse 

effects in a child.

The EPA has determined that lifetime exposure to 1 ppm 

boron is not expected to cause any adverse effects.

The Occupational Health and Safety Administration 

(OSHA) has limited workers’ exposure to an average of 

15 mg/m3 for boron oxide in air for an 8-hour workday, 

40-hour workweek.

References

Agency for Toxic Substances and Disease Registry (ATSDR). 

2007. Toxicological Profile for Boron (Draft for Public 

Comment). Atlanta, GA: U.S. Department of Health and 

Human Services, Public Health Service.

Where can I get more information?

For more information, contact the Agency for Toxic Substances and Disease Registry, Division of Toxicology and 

Human Health Sciences, 1600 Clifton Road NE, Mailstop F-57, Atlanta, GA 30333. 

Phone: 1-800-232-4636

ToxFAQsTM Internet address via WWW is http://www.atsdr.cdc.gov/toxfaqs/index.asp. 

ATSDR can tell you where to find occupational and environmental health clinics. Their specialists can recognize, evaluate, 

and treat illnesses resulting from exposure to hazardous substances. You can also contact your community or state 

health or environmental quality department if you have any more questions or concerns.