PUBLIC HEALTH STATEMENT 

NITROPHENOLS 

CAS#: 2-Nitrophenol 88-75-5 

4-Nitrophenol 100-02-7 

Division of Toxicology July 1992 

This Public Health Statement is the summary chapter 

from the Toxicological Profile for Nitrophenols. 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 Statement was prepared to give you information 

about 2-nitrophenol and 4-nitrophenol and to 

emphasize the human health effects that may result 

from exposure to them. The Environmental 

Protection Agency (EPA) has identified 1,177 

National Priorities List (NPL) sites. Nitrophenols 

have been found at 14 of these sites. However, we do 

not know how many of the 1,177 NPL sites have 

been evaluated for 2-nitrophenol and 4-nitrophenol. 

As EPA evaluates more sites, the number of sites at 

which nitrophenols are found may change. This 

information is important for you because 

nitrophenols may cause harmful effects and because 

these sites are potential or actual sources of human 

exposure to 2-nitrophenol and 4-nitrophenol. 

When a chemical is released from a large area, such 

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

drum or bottle, it enters the environment as a 

chemical emission. This emission, which is also 

called a release, does not always lead to exposure. 

You can be exposed to a chemical only when you 

come into contact with it. You may be exposed to it 

in the environment by breathing, eating, or drinking 

substances containing the chemical, or from skin 

contact with it. 

If you are exposed to a hazardous substance such as 

nitrophenols, several factors will determine whether 

harmful health effects will occur and what the type 

and severity of those health effects will be. These 

factors include the dose (how much), the duration 

(how long), the route or pathway by which you are 

exposed (breathing, eating, drinking, or skin contact), 

the other chemicals to which you are exposed, and 

your individual characteristics such as age, sex, 

nutritional status, family traits, life style, and state of 

health. 

1.1 WHAT ARE NITROPHENOLS? 

The two nitrophenols are very similar in their 

chemical properties. The manufacture of one almost 

always produces at least a little of the other. 

Therefore, we include them both in one profile. 2-

Nitrophenol is a light yellow solid with a peculiar 

aromatic smell. 4-Nitrophenol is a colorless to light 

yellow solid with very little odor. 2-Nitrophenol is 

slightly soluble in cold water, but 4-nitrophenol is 

moderately soluble in cold water. Neither chemical 

evaporates at room temperature. These are man-made 

chemicals with no evidence of their formation from 

any natural source. Therefore, humans are solely 

responsible for the presence of the chemicals in the 

environment. The main sources of the two chemicals 

are industrial manufacturing and processing. 2-

Nitrophenol is used mainly to produce dyes, paint 

coloring, rubber chemicals, and substances that kill 

molds (fungicides). 4-Nitrophenol is used mainly to 

manufacture drugs, fungicides, and dyes, and to 

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 

NITROPHENOLS 

CAS#: 2-Nitrophenol 88-75-5 

4-Nitrophenol 100-02-7 

Division of Toxicology July 1992 

darken leather. The time needed for these two 

chemicals to disappear chemically in air is not 

known. They both break down (degrade) in water and 

surface soil, but the breakdown takes longer at lower 

soil depths and in groundwater. Therefore, they are 

expected to stay longer in the deep soil of dump sites 

compared to surface soil and may even stay 

indefinitely in these soils 

1.2 HOW MIGHT I BE EXPOSED TO 

NITROPHENOLS? 

Small amounts of the two substances can be found in 

the air, water, and soil. Therefore, breathing air, 

drinking water, and eating foods grown in soils that 

contain these substances can expose you to them. The 

background levels (when no apparent sources of 

pollution are present) of the two nitrophenols in air 

are not known. However, in one case, the level of 2-

nitrophenol in the air in Portland, Oregon, was 4 parts 

per trillion (ppt by volume). Its level in the air in 

Dubendorf, Switzerland, was 61 ppt. These are very 

small numbers, and exposure from breathing air 

containing such low levels of these substances may 

not be very harmful. Except for one case of polluted 

water, these two substances have not been found in 

U.S. public drinking waters. The background levels 

of these compounds in foods eaten by humans are not 

known either. Because the chemicals break down 

rapidly, any exposure from these levels will be small. 

4-Nitrophenol has been found in the urine of people 

who did not have any known exposure to this 

substance. The 4-nitrophenol found in human urine 

comes from the breakdown within the body of a 

pesticide, parathion, that is commonly used on certain 

agricultural products that many of us eat. 

Some people may be exposed to higher than 

background levels of nitrophenols. Workers who 

produce or process these chemicals may be exposed 

to higher doses, particularly during spills or 

accidents. Workers involved in cleaning up 

hazardous waste or spills that contain these chemicals 

and pesticide applicators are especially subjected to 

higher than background levels of exposure. People 

who use certain pesticides or who drink well water 

near farming areas where certain pesticides are used 

may also be exposed to higher than background 

levels of 4-nitrophenol. The two nitrophenols and 

their mixture have been found in at least 14 of the 

1,177 hazardous waste sites on the National Priorities 

List (NPL). People who live near these sites may be 

subjected to exposure at higher doses than 

background. Except for the high levels of 4-

nitrophenol found in the urine of persons exposed to 

the pesticide, parathion, we have no evidence of 

exposure to 2-nitrophenol and 4-nitrophenol that is 

higher than background levels. 

1.3 HOW CAN NITROPHENOLS ENTER AND 

LEAVE MY BODY? 

2-Nitrophenol and 4-nitrophenol can enter your body 

through your lungs and pass into the blood stream if 

you breathe contaminated air. If you swallow 2-

nitrophenol or 4-nitrophenol, most of it probably 

enters your body and passes from the stomach into 

the blood stream very quickly (in minutes). If you 

spill 2-nitrophenol or 4-nitrophenol on your skin, 

some of it might pass through the skin into the blood 

stream, but we do not know how much or how fast. 

Once inside your body, 2-nitrophenol and 4-

nitrophenol change (we call this change metabolism) 

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 

NITROPHENOLS 

CAS#: 2-Nitrophenol 88-75-5 

4-Nitrophenol 100-02-7 

Division of Toxicology July 1992 

into other chemicals that will be quickly (in hours) 

released from the body in your urine. We do not have 

enough information available to determine which will 

be the most likely way that 2-nitrophenol or 4-

nitrophenol will enter your body if you are exposed at 

hazardous waste sites. 

1.4 HOW CAN NITROPHENOLS AFFECT MY 

HEALTH? 

How a chemical affects your health depends on how 

much you are exposed to and for how long. As the 

level and length of your exposure increase, the effects 

are likely to become more severe. Rats that breathed 

dusts of 4-nitrophenol for 2 weeks developed a blood 

disorder which reduces the ability of the blood to 

carry oxygen to tissues and organs. However, these 

abnormalities disappeared a few days after exposure 

stopped. Chemicals like the nitrophenols cause a 

similar blood disorder in humans, and so humans 

exposed for weeks or longer to high levels of 

nitrophenols may develop the same types of blood 

disorders that animals do. Experimental studies have 

shown that 4-nitrophenol is more harmful than 2-

nitrophenol in animals. There is no information on 

the effects on human health from breathing dusts of 

2-nitrophenol or 4-nitrophenol. 

Some rats, mice, and rabbits that swallowed large 

amounts of 2-nitrophenol or 4-nitrophenol died 

within a few days, but we do not know the exact 

cause of death. Some rats that swallowed smaller 

amounts of 4-nitrophenol for a few weeks also died, 

but those that survived had no apparent harmful 

health effects. No birth defects were found in the 

offspring of pregnant mice that swallowed 4-

nitrophenol. We do not know if swallowing very 

small amounts of 2-nitrophenol or 4-nitrophenol for 

many months or years leads to serious disease or 

death. There is no information on their health effects 

from humans who ate food or drank water 

contaminated with these chemicals. 

Rats and rabbits that had relatively large amounts of 

4-nitrophenol applied to their skin for a day or less 

had skin irritation. Rats that had a small amount of 4-

nitrophenol on their skin for a few months also had 

skin irritation. 4-Nitrophenol also caused eye 

irritation in rabbits when it was applied to the eye. It 

appears that exposure of animals to very small 

amounts of 2-nitrophenol or 4-nitrophenol by skin 

contact for many months does not lead to serious 

disease or death. We do not know whether breathing 

dusts of these chemicals or spilling them on your skin 

can cause birth defects, affect fertility, or cause 

cancer. 

1.5 IS THERE A MEDICAL TEST TO 

DETERMINE WHETHER I HAVE BEEN 

EXPOSED TO NITROPHENOLS? 

Although methods are available for measuring levels 

of 4-nitrophenol in the urine and blood, they are 

probably not useful unless the exposure was very 

recent. 4-Nitrophenol passes out of the body through 

urine within a few hours. Because the effects usually 

seen on the blood may also result from causes besides 

4-nitrophenol, these effects alone cannot be used to 

prove exposure. No tests are available to tell whether 

you have been exposed to 2-nitrophenol. 

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 

NITROPHENOLS 

CAS#: 2-Nitrophenol 88-75-5 

4-Nitrophenol 100-02-7 

Division of Toxicology July 1992 

1.6 WHAT RECOMMENDATIONS HAS THE 

FEDERAL GOVERNMENT MADE TO 

PROTECT HUMAN HEALTH? 

In order to minimize exposure to nitrophenols by 

humans the Environmental Protection Agency (EPA) 

says that industry must tell the National Response 

Center when 100 pounds or more of 2-nitrophenol or 

4-nitrophenol have been disposed of. 

1.7 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: 

Agency for Toxic Substances and Disease Registry 

Division of Toxicology 

1600 Clifton Road NE, Mailstop F-32 

Atlanta, GA 30333 

Information line and technical assistance: 

Phone: 888-422-8737 

FAX: (770)-488-4178 

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. 

To order toxicological profiles, contact: 

National Technical Information Service 

5285 Port Royal Road 

Springfield, VA 22161 

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

Reference 

Agency for Toxic Substances and Disease Registry 

(ATSDR). 1992. Toxicological profile for 

nitrophenols. Atlanta, GA: U.S. Department of 

Health and Human Services, Public Health Service. 

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