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PUBLIC HEALTH STATEMENT 

Dichlorobenzenes 

CAS#: 1,2-Dichlorobenzene, 95-50-1; 1,3 Dichlorobenzene, 541-73-1; 

1,4-Dichlorobenzene, 106-46-7 

Division of Toxicology and Environmental Medicine August 2006 

This Public Health Statement is the summary 

chapter from the Toxicological Profile for 

Dichlorobenzenes. It is one in a series of Public 

Health Statements about hazardous substances and 

their health effects. A shorter version, the 

ToxFAQsTM, 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 

1-888-422-8737. 

This public health statement tells you about 

dichlorobenzenes (DCBs) and the effects of 

exposure to them. 

The Environmental Protection Agency (EPA) 

identifies the most serious hazardous waste sites in 

the nation. These sites are then placed on the 

National Priorities List (NPL) and are targeted for 

long-term federal clean-up activities. 1,2-, 1,3-, and 

1,4-Dichlorobenzene have been identified in at least 

281, 175, and 330, respectively, of the 1,662 current 

or former NPL sites. Although the total number of 

NPL sites evaluated for these substances is not 

known, the possibility exists that the number of 

sites at which dichlorobenzenes are found may 

increase in the future as more sites are evaluated. 

This information is important because these sites 

may be sources of exposure and exposure to these 

substances may harm you. 

When a substance is released either from a large 

area, such as an industrial plant, or from a container, 

such as a drum or bottle, it enters the environment. 

Such a release does not always lead to exposure. 

You can be exposed to a substance only when you 

come in contact with it. You may be exposed by 

breathing, eating, or drinking the substance, or by 

skin contact. 

If you are exposed to dichlorobenzenes, many 

factors will determine whether you will be harmed. 

These factors include the dose (how much), the 

duration (how long), and how you come in contact 

with them. You must also consider any other 

chemicals you are exposed to and your age, sex, 

diet, family traits, lifestyle, and state of health. 

1.1 WHAT ARE DICHLOROBENZENES? 

Each of the three types of DCBs (i.e., 1,2-DCB, 

1,3-DCB, and 1,4-DCB) contains two chlorine 

atoms connected to one benzene molecule. 

1,2-DCB is a colorless to pale yellow liquid used to 

make herbicides. 1,3-DCB is a colorless liquid used 

to make herbicides, insecticides, medicine, and 

dyes. 1,4-DCB, the most important of the three 

chemicals, is a colorless to white solid. It smells 

like mothballs and it is one of two chemicals 

commonly used to make mothballs. 1,4-DCB also 

is used to make deodorant blocks used in garbage 

cans and restrooms, and to help control odors in 

animal-holding facilities. 1,4-DCB has been used 

as an insecticide on fruit and as an agent to control 

mold and mildew growth on tobacco seeds, leather, 

and some fabrics. Recently, using 1,4-DCB to 

make resins has become very important. 

When a package of 1,4-DCB is opened, it 

‘sublimates’, that is, it slowly changes from a solid 

into a vapor, and enters the atmosphere. The vapor 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Dichlorobenzenes 

CAS#: 1,2-Dichlorobenzene, 95-50-1; 1,3 Dichlorobenzene, 541-73-1; 

1,4-Dichlorobenzene, 106-46-7 

Division of Toxicology and Environmental Medicine August 2006 

acts as a deodorizer and insect killer. Most of the 

1,2-, 1,3-, and 1,4-DCB released into the 

environment is present as a vapor. DCBs can burn, 

but they do not burn easily. Most people begin to 

smell 1,4-DCB when it is in the air at a 

concentration of 0.18 parts per million (ppm) and 

0.011 ppm in water. 

DCBs do not occur naturally; chemical companies 

produce them to make products for home use and 

other chemicals such as herbicides and plastics. 

1.2 WHAT HAPPENS TO 

DICHLOROBENZENES WHEN THEY 

ENTER THE ENVIRONMENT? 

Most of the 1,4-DCB enters the environment when 

it is used in mothballs and in toilet-deodorizer 

blocks. Some 1,4-DCB is released to the air by 

factories that make or use it, and only a little is 

released to soil and water. Very little 1,4-DCB 

enters the environment from hazardous waste sites. 

Some 1,2- and 1,3-DCBs are released into the 

environment when used to make herbicides and 

when people use products that contain these 

chemicals. Companies that make 1,4-DCB also 

make unwanted amounts of 1,2-DCB during the 

process. 1,2-DCB is released to the environment 

when companies dispose of these unwanted 

supplies. 

Because DCBs do not dissolve easily in water, the 

small amounts that enter water quickly evaporate 

into the air. If they are released to groundwater, 

they may be transported through the ground to 

surface water. Sometimes, DCBs bind to soil and 

sediment. DCBs in soil usually are not easily 

broken down by soil organisms. Evidence suggests 

that plants and fish absorb DCBs. 1,4-DCB has 

been detected at concentrations of up to 470 parts 

per billion (ppb) in fish. 

1.3 HOW MIGHT I BE EXPOSED TO 

DICHLOROBENZENES? 

Humans are exposed to 1,4-DCB mainly by 

breathing vapors from 1,4-DCB products used in 

the home, such as mothballs and toilet-deodorizer 

blocks. Reported levels of 1,4-DCB in some homes 

and public restrooms have ranged from 0.291 to 

272 parts of 1,4-DCB per billion parts (ppb) of air. 

1,2- and 1,3-DCB are not found frequently in the air 

of homes and buildings because, unlike 1,4-DCB, 

these chemicals are not used in household products. 

Outdoor levels of 1,4-DCB range from 0.01 to 

1 ppb and are much lower than levels in homes and 

buildings. Levels in the air around hazardous waste 

sites are low and range from 0.01 to 4.2 ppb. 

Outdoor air levels generally range from 0.01 to 

0.1 ppb for 1,2-DCB and from 0.001 to 0.1 ppb for 

1,3-DCB. 

DCBs have been found in samples of drinking water 

from surface water sources. 1,4-DCB was found in 

13% of surface water samples collected during a 

national survey. These samples contained about 

0.008–154 ppb of 1,4-DCB. DCBs also have been 

found in drinking water from wells but at low 

concentrations. DCBs are found only infrequently 

in soil, but they have been detected in soil around 

hazardous waste sites in the United States. 

DCBs have been detected in beef, pork, chicken, 

eggs, baked goods, soft drinks, butter, peanut butter, 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Dichlorobenzenes 

CAS#: 1,2-Dichlorobenzene, 95-50-1; 1,3 Dichlorobenzene, 541-73-1; 

1,4-Dichlorobenzene, 106-46-7 

Division of Toxicology and Environmental Medicine August 2006 

fruits, vegetables, and fish. However, the levels of 

DCBs in foods are generally low. 

The average daily adult intake of 1,4-DCB is about 

35 micrograms (μg), which comes mainly from 

breathing 1,4-DCB vapors released from products 

in homes and businesses. The average daily adult 

respiratory exposure of the other DCBs is about 

1.8 μg for 1,2-DCB and about 0.8 μg for 1,3-DCB. 

Individuals can be occupationally exposed to DCBs 

in workplace air at much higher levels than the 

general public is exposed. Levels measured in the 

air of factories that make or process 1,4-DCB 

products have ranged from 5.6 to 748 ppm of air. 

In addition, people who live or work near industrial 

facilities or hazardous waste sites that have high 

levels of DCBs may have greater exposure to these 

compounds due to emissions from the facilities and 

waste sites. People who work or live in buildings 

where air fresheners, toilet block deodorants, or 

moth balls containing 1,4-DCB are used also are 

expected to have a higher exposure to this 

compound, which could occur from skin contact as 

well as by breathing. 

1.4 HOW CAN DICHLOROBENZENES 

ENTER AND LEAVE MY BODY? 

The main way DCBs enter your body is through the 

lungs when you breathe in DCB vapors released in 

the workplace or in the home from use of products 

that contain it. When you breathe in these 

chemicals for a few hours, it is likely that some of 

the DCBs that have entered your body will get into 

your bloodstream. 

DCBs also can get into your body if you drink water 

or eat certain foods that contain them, such as meat, 

chicken, eggs, or fish. Most of the DCBs that enter 

your body from food and water will get into your 

bloodstream. It is not likely that DCBs will enter 

your body through the skin if you touch products 

that contain them. 

1,4-DCB used in the home could be accidentally 

swallowed, especially by young children. This 

possibility exists because household products that 

contain 1,4-DCB, particularly some kinds of 

mothballs and deodorant blocks, might be freely 

available in closets or bathrooms. 

Most of the DCB that enters your body (perhaps 

more than 95%) leaves through the urine in less 

than a week. Small amounts (perhaps 1–2%) leave 

your body in the feces and in the air you breathe 

out. Tiny amounts remain in your fat and might 

stay there for a long time. 

Most of the DCBs that enter your body are changed 

into other chemicals, mainly dichlorophenols. It is 

not known if these breakdown products are more or 

less harmful than the DCBs themselves. 

1.5 HOW CAN DICHLOROBENZENES 

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. 

One way to learn whether a chemical will harm 

people is to determine how the body absorbs, uses, 

and releases the chemical. For some chemicals, 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

__________________________________________________________________________________________ 

 

PUBLIC HEALTH STATEMENT 

Dichlorobenzenes 

CAS#: 1,2-Dichlorobenzene, 95-50-1; 1,3 Dichlorobenzene, 541-73-1; 

1,4-Dichlorobenzene, 106-46-7 

Division of Toxicology and Environmental Medicine August 2006 

animal testing may be necessary. Animal testing 

may also help identify health effects such as cancer 

or birth defects. Without laboratory animals, 

scientists would lose a basic method for getting 

information needed to make wise decisions that 

protect public health. Scientists have the 

responsibility to treat research animals with care 

and compassion. Scientists must comply with strict 

animal care guidelines because laws today protect 

the welfare of research animals. 

Most of the information on health effects of DCBs 

is from studies of 1,2- and 1,4-DCB. Very little is 

known about the health effects of 1,3-DCB, 

especially in humans, but they are likely to be 

similar to those of the other DCBs. 

Inhaling the vapor or dusts of 1,2-DCB and 

1,4-DCB at very high concentrations could be very 

irritating to your eyes and nose and cause burning 

and tearing of the eyes, coughing, difficult 

breathing, and an upset stomach. These 

concentrations could occur in workplaces, but are 

much higher than you would be exposed to in the 

home. 1,4-DCB is the only DCB that is commonly 

used in household products (mainly mothballs and 

toilet-deodorizer blocks). Scientists have no clear 

evidence that the moderate use of common 

household products containing 1,4 DCB will cause 

any problems to your health. A recent study reports 

limited evidence suggesting that inhalation 

exposure to 1,4-DCB may result in decreases in 

lung function. Some people reported health 

problems, such as dizziness, headaches, and liver 

problems, from very high levels of 1,4-DCB in the 

home. However, these people used very high 

amounts of 1,4-DCB products and continued to use 

the products for months or even years, even though 

they felt ill. People who ate 1,4-DCB products 

regularly for long periods (months to years) because 

of its sweet taste developed skin blotches and 

problems with red blood cells, such as anemia (ironpoor blood). Little information is available about 

the effects of skin contact with DCBs. 1,4-DCB 

might cause a burning feeling in your skin if you 

hold mothballs or toilet-deodorizer blocks against 

your skin for a long time. 

Breathing or eating any of the DCBs caused 

harmful effects in the liver of laboratory animals. 

Animal studies also found that 1,2-DCB and 

1,4-DCB caused effects in the kidneys and blood, 

and that 1,3-DCB caused thyroid and pituitary 

effects. There is no clear evidence that 1,2-DCB 

and 1,4-DCB impair reproduction or fetal 

development in animals at levels below those that 

also cause serious health effects in the mother, 

although there is an indication that 1,4-DCB can 

affect development of the nervous system after 

birth. 

Lifetime exposure to 1,4-DCB by breathing or 

eating induced liver cancer in mice. 1,2-DCB was 

not carcinogenic in laboratory animals, and 

1,3-DCB has not been tested for its potential to 

cause cancer. The animal studies suggest that 

1,4-DCB could play a role in the development of 

cancer in humans, but we do not definitely know 

this. The U.S. Department of Health and Human 

Services (DHHS) has determined that 1,4-DCB 

might be a human carcinogen. The International 

Agency for Research on Cancer (IARC) determined 

that 1,4-DCB is possibly carcinogenic to humans. 

Both IARC and the EPA concluded that 1,2-DCB 

and 1,3-DCB are not classifiable as to human 

carcinogenicity. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Dichlorobenzenes 

CAS#: 1,2-Dichlorobenzene, 95-50-1; 1,3 Dichlorobenzene, 541-73-1; 

1,4-Dichlorobenzene, 106-46-7 

Division of Toxicology and Environmental Medicine August 2006 

1.6 HOW CAN DICHLOROBENZENES 

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 exposed to DCBs in many of the same 

ways adults are. It is possible that mothballs and 

toilet bowl deodorant blocks containing 1,4-DCB 

could be played with or accidentally swallowed, 

especially by young children. Because children 

tend to be curious about unknown powders and 

liquids, and because these products might be easily 

accessible in cabinets, closets, or bathrooms, 

children could be at a higher risk of exposure to 

1,4-DCB than adults. 

Children who are exposed to DCBs are likely to 

exhibit the same effects as adults, although this is 

not known for certain. Thus, all health problems of 

DCBs observed in adults are of potential concern in 

children. 

Children can also be exposed to DCBs prenatally, 

because all three isomers have been detected in 

placenta samples, as well as through breast feeding. 

There is no reliable evidence suggesting that DCBs 

cause birth defects, although animal data raise 

concern for effects of 1,4-DCB on postnatal 

development of the nervous system. 

1.7 HOW CAN FAMILIES REDUCE THE 

RISK OF EXPOSURE TO DICHLOROBENZENES? 

If your doctor finds that you have been exposed to 

substantial amounts of DCBs, ask whether your 

children might also have been exposed. Your 

doctor might need to ask your state health 

department to investigate. 

You and your children could be exposed to 

1,4-DCB in your home if you use consumer 

products that contain 1,4-DCB, such as some toilet 

bowl cleaners and mothballs. Exposure of children 

to 1,4-DCB can be minimized by discouraging them 

from playing with, swallowing, or having skin 

contact with treated products. These items should 

be stored out of reach of young children and kept in 

their original containers to prevent accidental 

poisonings. Keep your Poison Control Center’s 

number by the phone. 

1.8 IS THERE A MEDICAL TEST TO 

DETERMINE WHETHER I HAVE BEEN 

EXPOSED TO DICHLOROBENZENES? 

Several tests can be used to show if you have been 

exposed to DCBs. The most commonly used tests 

measure their dichlorophenol breakdown products 

in urine and blood. These tests require special 

equipment that is not routinely available in a 

doctor's office, but they can be performed in a 

special laboratory. 

The presence of the dichlorophenol breakdown 

products in the urine indicates a person has been 

exposed to DCBs within the previous day or two. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

__________________________________________________________________________________________ 

 

PUBLIC HEALTH STATEMENT 

Dichlorobenzenes 

CAS#: 1,2-Dichlorobenzene, 95-50-1; 1,3 Dichlorobenzene, 541-73-1; 

1,4-Dichlorobenzene, 106-46-7 

Division of Toxicology and Environmental Medicine August 2006 

For example, detection of 2,5-dichlorophenol in 

urine is commonly used to determine worker 

exposure to 1,4-DCB in industrial settings. Another 

test measures levels of DCBs in your blood, but this 

is used less often. Neither of these tests can be used 

to show how high the level of DCB exposure was or 

to predict whether harmful health effects will 

follow. 

1.9 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 

dichlorobenzenes include the following: 

The federal government has taken a number of steps 

to protect people from excessive exposure to DCBs. 

EPA has listed 1,2-, 1,3-, and 1,4-DCB as 

hazardous wastes and subjects them to hazardous 

waste regulations. EPA has set maximum levels of 

600 micrograms (μg) of 1,2-DCB and 75 μg of 

1,4-DCB per liter of drinking water. 1,4-DCB is a 

pesticide registered with EPA, and its 

manufacturers must provide certain kinds of 

information to EPA for it to be registered for use as 

a pesticide. OSHA has set maximum levels of 

50 ppm for 1,2-DCB and 75 ppm for 1,4-DCB in 

workplace air for an 8-hour day, 40-hour 

workweek. 

1.10 WHERE CAN I GET MORE 

INFORMATION? 

If you have any more questions or concerns, please 

contact your community or state health or 

environmental quality department, or contact 

ATSDR at the address and phone number below. 

ATSDR can also tell you the location of 

occupational and environmental health clinics. 

These clinics specialize in recognizing, evaluating, 

and treating illnesses that result from exposure to 

hazardous substances. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

__________________________________________________________________________________________ 

 

PUBLIC HEALTH STATEMENT 

Dichlorobenzenes 

CAS#: 1,2-Dichlorobenzene, 95-50-1; 1,3 Dichlorobenzene, 541-73-1; 

1,4-Dichlorobenzene, 106-46-7 

Division of Toxicology and Environmental Medicine August 2006 

Toxicological profiles are also available on-line at 

www.atsdr.cdc.gov and on CD-ROM. You may 

request a copy of the ATSDR ToxProfilesTM CDROM by calling the toll-free information and 

technical assistance number at 1-888-42ATSDR 

(1-888-422-8737), by e-mail at atsdric@cdc.gov, or 

by writing to: 

Agency for Toxic Substances and Disease Registry 

Division of Toxicology and Environmental 

Medicine 

1600 Clifton Road NE 

Mailstop F-32 

Atlanta, GA 30333 

Fax: 1-770-488-4178 

Organizations for-profit may request copies of final 

Toxicological Profiles from the following: 

National Technical Information Service (NTIS) 

5285 Port Royal Road 

Springfield, VA 22161 

Phone: 1-800-553-6847 or 1-703-605-6000 

Web site: http://www.ntis.gov/ 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov