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PUBLIC HEALTH STATEMENT 

Phosphate Ester Flame Retardants 

Division of Toxicology and Environmental Medicine September 2009 

This Public Health Statement is the summary chapter from the Toxicological Profile for Phosphate Ester 

Flame Retardants. 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 these substances 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. 

This public health statement tells you about phosphate ester flame retardants and the effects of exposure 

to them. 

This profile discusses the following phosphate ester flame retardants: tris(2-chloroethyl) phosphate 

(TCEP), tributyl phosphate (TnBP), tris(2-butoxyethyl) phosphate (TBEP), tris(1,3-dichloro-2-propyl) 

phosphate (TDCP), triphenyl phosphate (TPP), tris(2-chloroisopropyl) phosphate (TCPP), and triisobutyl 

phosphate (TiBP). 

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. Phosphate ester flame retardants have been found in at least 8 of the 

1,699 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 phosphate ester flame retardants 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 be harmful. 

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. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry
 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Phosphate Ester Flame Retardants 

Division of Toxicology and Environmental Medicine September 2009 

If you are exposed to phosphate ester flame retardants, 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 PHOSPHATE ESTER FLAME RETARDANTS? 

Description Phosphate ester flame retardants are human-made chemicals added 

to consumer and industrial products for the purpose of reducing 

flammability. 

Phosphate ester flame retardants are composed of a group of 

chemicals with similar properties but slightly different structures. 

Phosphate esters are typically liquids at room temperature; however, 

some are solids. 

Uses Phosphate esters are flame retardants, plasticizers, hydraulic fluids, 

solvents, extraction agents, antifoam agents, and coatings for 

electronic devices. 

1.2 WHAT HAPPENS TO PHOSPHATE ESTER FLAME RETARDANTS WHEN THEY 

ENTER THE ENVIRONMENT? 

Sources Phosphate ester flame retardants are released to the environment 

from industrial sources and disposal of consumer products containing 

flame retardants. 

Breakdown Phosphate ester flame retardants can change chemical composition 

in the environment. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry
 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Phosphate Ester Flame Retardants 

Division of Toxicology and Environmental Medicine September 2009 

• Air There is no information available that suggests the selected 

phosphate ester flame retardants undergo transformation or 

degradation in the atmosphere. Particulate-phase phosphate esters 

are subject to wet and dry deposition, while semi-volatile phosphate 

esters have the potential to hydrolyze to diesters, monoesters, and 

phosphoric acid. 

• Water and soil Generally, most phosphate esters are poorly soluble in water and 

adsorb strongly to soils. These compounds are considered emerging 

pollutants due to their prevalence and persistence in the environment. 

Phosphate esters are subject to biodegradation in aquatic and 

terrestrial environments. 

1.3 HOW MIGHT I BE EXPOSED TO PHOSPHATE ESTER FLAME RETARDANTS?
 

Routes of exposure Humans can be exposed by a combination of oral, inhalation, and 

dermal routes. 

Food—primary source 

of exposure 

Ingesting contaminated food: Most foods have been found to contain 

trace amounts of phosphate ester flame retardants due to their wide 

use in plastics and presence in the environment. 

Air Breathing contaminated outdoor air: Hydraulic fluid is the primary 

source of phosphate esters in outdoor air. 

Breathing contaminated indoor air: Indoor air can contain phosphate 

ester flame retardants from certain plastics, adhesives, foams, or 

electronics. 

Water and soil Drinking water contaminated with phosphate esters due to leaching 

from plastics or industrial waste water discharge. 

By skin contact with contaminated soil: Hydraulic fluid spills or 

industrial waste water used for agriculture can result in the presence 

of phosphate esters in soil. 

Children Young children may be at a higher risk of exposure since they are 

more likely to put phosphate ester flame retardant treated materials in 

their mouths. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry
 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Phosphate Ester Flame Retardants 

Division of Toxicology and Environmental Medicine September 2009 

1.4 HOW CAN PHOSPHATE ESTER FLAME RETARDANTS ENTER AND LEAVE MY 

BODY? 

Enter the body 

• Humans 

• Animals 

There is virtually no information about the entrance of these 

substances into the body. However, TDCP had been found in human 

tissues and body fluids, so we know that this substance can enter the 

body possibly by inhaling aerosols or dusts or ingesting contaminated 

food or water. 

Oral – Studies found that TDCP, TCEP, and TnBP can easily pass 

from the stomach and intestines to the blood stream. 

Dermal – Less amounts entered the body through the skin of rats and 

only very small amounts through the skin of pigs. 

Leave the body 

• Humans 

• Animals 

There is no information on how these chemicals leave your body, but 

based on studies in animals, phosphate ester flame retardants may 

be broken down in the body and the breakdown product may be 

eliminated in the urine. However, there are no studies in humans to 

prove that this actually happens. 

Neither phosphate ester flame retardants nor their breakdown 

products seemed to accumulate in the body. Most breakdown 

products were eliminated in the urine in 2–3 days. 

1.5 HOW CAN PHOSPHATE ESTER FLAME RETARDANTS AFFECT MY HEALTH? 

This section looks at animal and human studies concerning potential health effects. 

Workers Long-term exposure of workers to TDCP or TPP was not associated 

with adverse health effects. No information was available regarding 

exposure to other phosphate ester flame retardants. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry
 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Phosphate Ester Flame Retardants 

Division of Toxicology and Environmental Medicine September 2009 

General population Almost no information is available regarding health effects in 

members of the general population exposed to the phosphate ester 

flame retardants discussed in this profile. 

There have been a few cases of allergic reactions to consumer 

products that contain TPP, but a study that examined several 

hundred people exposed to plastics and glues that contained TPP did 

not find any allergic reactions. 

Laboratory animals One way to learn about the effects of phosphate ester flame 

retardants is to see how they affect test animals. Almost all studies in 

animals have administered these substances orally and generally at 

levels much higher than what can be expected from environmental 

exposures. 

TCEP given to rats for 16 weeks or longer caused brain lesions. 

When given for 2 years, it also caused lesions in the kidneys. TCEP 

also decreased the fertility of mice that were exposed for 18 weeks 

before mating. 

TnBP induced lesions in the urinary bladder of rats when given for 

10 weeks or longer. 

TBEP caused liver lesions in rats after the rats ate food that 

contained TBEP for 18 weeks. 

Rats that ate food containing TDCP for 2 years developed lesions in 

the kidneys and liver. 

The few studies that examined the effects of TPP, TiBP, and TCPP in 

animals did not report significant adverse health effects. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry
 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Phosphate Ester Flame Retardants 

Division of Toxicology and Environmental Medicine September 2009 

Cancer There is not enough information available to determine with certainty 

whether or not phosphate ester flame retardants produce cancer in 

humans. 

A study of workers employed in the manufacture of TDCP did not find 

significant associations between exposure to TDCP and cancer. No 

information was available regarding the carcinogenic potential of the 

other phosphate esters to humans. 

Rats that received oral doses of TCEP for 2 years developed kidney 

tumors. Feeding mice a diet that contained TCEP for 18 months 

induced tumors in the kidney, liver, and stomach, and also induced 

leukemia. Long-term administration of TnBP to rats and mice 

induced tumors in the urinary bladder and the liver, respectively. 

Feeding rats with a diet that contained TDCP for 2 years produced 

tumors in the liver, kidneys, testes, and adrenal gland. 

Neither the EPA nor the Department of Health and Human Services 

(DHHS) has classified the carcinogenic potential of the phosphate 

esters discussed in this profile. The International Agency for 

Research on Cancer (IARC) determined that TCEP is not classifiable 

as to its carcinogenicity to humans. 

1.6 HOW CAN PHOSPHATE ESTER FLAME RETARDANTS AFFECT CHILDREN? 

This section discusses potential health effects in humans from exposures during the period from 

conception to maturity at 18 years of age. 

Effects in humans There are no studies that examined the health effects of the 

phosphate ester flame retardants discussed in this profile on 

pregnant women or on their embryo or fetus. 

There are no studies that examined the health effects in children of 

the phosphate ester flame retardants discussed in this document. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry
 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Phosphate Ester Flame Retardants 

Division of Toxicology and Environmental Medicine September 2009 

Laboratory animals In general, exposure of rodents during gestation to TCEP, TnBP, 

TBEP, TDCP, TPP, or TCPP did not result in adverse effects to the 

fetuses or newborn animals. 

However, continuous exposure of two generations of mice to TCEP 

reduced the number of male pups born alive in the third generation. 

A similar study with TnBP in rats found that pups born to exposed rats 

had lower body weight during the first weeks of life than pups born to 

untreated rats. 

Exposure of the fetus There is no information regarding transfer of phosphate ester flame 

retardants to the fetus across the placenta in pregnant women. 

Human breast milk No studies have been conducted to determine whether phosphate 

ester flame retardants can be detected in human breast milk from 

women exposed at work or from the general population. 

1.7 HOW CAN FAMILIES REDUCE THE RISK OF EXPOSURE TO PHOSPHATE ESTER 

FLAME RETARDANTS? 

Food Avoid food that is generally high in phosphate ester content as 

indicated by the current market basket for the U.S. Total Diet study. 

Air Avoid installation or use of materials that are known to contain 

phosphate ester-based flame retardants in indoor environments to 

minimize exposure to them via air and particulate matter. 

1.8 IS THERE A MEDICAL TEST TO DETERMINE WHETHER I HAVE BEEN EXPOSED TO 

PHOSPHATE ESTER FLAME RETARDANTS? 

Detecting exposure Phosphate ester flame retardants can be measured in blood and 

urine, but this is not a routine test that can be performed in a doctor’s 

office. You should, however, see a physician if you believe that you 

have been exposed to high levels of these substances. 

No studies have been conducted to measure these chemicals in 

blood samples from groups of people representative of the U.S. 

general population. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry
 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Phosphate Ester Flame Retardants 

Division of Toxicology and Environmental Medicine	 September 2009 

Measuring exposure The presence of phosphate ester flame retardants in your blood may 

indicate that you have been exposed to these substances and some 

amount entered your bloodstream. 

The presence of phosphate ester flame retardants in your blood does 

not necessarily indicate that adverse health effects will occur. 

Additional studies are needed to help to determine the health effects 

associated with exposure to these substances. 

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. These are levels of a toxic 

substance in air, water, soil, or food that do not exceed a critical value. This critical value 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. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry
 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Phosphate Ester Flame Retardants 

Division of Toxicology and Environmental Medicine September 2009 

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 phosphate ester flame retardants include the following: 

Levels in workplace air 

set by OSHA 

OSHA set a legal limit of 3 and 5 mg/m3 for TPP and TnBP, 

respectively, in air averaged over an 8-hour work day. 

Food The EPA has permitted TnBP, TBEP, and TPP for use in nonfood 

pesticide products. 

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. 

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 CD-ROM by calling the toll-free information and technical 

assistance number at 1-800-CDCINFO (1-800-232-4636), by e-mail at cdcinfo@cdc.gov, or by writing 

to: 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry
 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Phosphate Ester Flame Retardants 

Division of Toxicology and Environmental Medicine September 2009 

Agency for Toxic Substances and Disease Registry
 

Division of Toxicology and Environmental Medicine
 

1600 Clifton Road NE
 

Mailstop F-62
 

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: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov