4-Nitrophenol (also called p-nitrophenol or 4-hydroxynitrobenzene) is a phenolic compound with the molecular formula C6H5NO3. [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][1] It is a colourless to light yellow solid with very little odour, which is not found naturally in the environment. [2]

Uses [3]

4-Nitrophenol is used to manufacture drugs (e.g., acetaminophen), fungicides, methyl and ethyl parathion insecticides, and dyes and to darken leather.

In the Environment [2]

  • Most 4-nitrophenol enters the environment during manufacturing and processing.
  • It can be formed in the air as a result of the breakdown of many other manufactured chemicals.
  • Most goes to water and soil; little goes to the air.
  • Very little is known about the fate of 4-nitrophenol in air.
  • It readily breaks down in surface water.
  • It takes a long time to break down in deep soil and in groundwater.
  • 4-nitrophenol has not been found in foods.
  • It is a breakdown product of other pesticides including parathion and fluoridifen.
  • It is also formed in auto exhaust.

Sources & Routes of Exposure

Sources of Exposure [2]

Exposure to 4-nitrophenol can occur via:

  • Air, water, and soil contaminated with the chemical.
  • Breathing contaminated workplace air with higher levels of the chemicals (especially during spills).
  • Breathing contaminated air (during application) or drinking contaminated water near farming areas where certain fungicides are used.
  • Breathing contaminated air or drinking contaminated water near waste sites and landfills.

Routes of Exposure [4]

4-nitrophenol can enter your body through your lungs and pass into the blood stream if you breathe contaminated air. If you swallow 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 4-nitrophenol on your skin, some of it might pass through the skin into the blood stream, but how much or how fast remains unknown. Once inside your body, 4- nitrophenol metabolise into other chemicals that will be quickly (in hours) released from the body in your urine.

Health Effects [3]

Acute Effects

Acute inhalation or ingestion of 4-nitrophenol in humans causes headaches, drowsiness, nausea, and cyanosis. Contact with the eyes causes irritation. A study examining the acute effects of 4-nitrophenol from inhalation exposure in rats reported an increase in methemoglobin and corneal opacity. Tests involving acute exposure of rats and mice have shown 4-nitrophenol to have high toxicity from oral and dermal exposure.

Chronic Effects

No information is available on the chronic effects of 4-nitrophenol in humans or animals from inhalation or oral exposure. An animal study examining the chronic effects of 4-nitrophenol from dermal exposure reported no effects on the respiratory, cardiovascular, gastrointestinal, muscular, immune, and central nervous systems, or the liver and kidney. The only effects noted were dermal irritation consisting of erythema, scaling, scabbing, and cracking of the skin. EPA has not established a Reference Concentration (RfC) or a Reference Dose (RfD) for 4-nitrophenol.

Reproductive/Developmental Effects

No information is available on the reproductive or developmental effects of 4-nitrophenol in humans. One animal study reported no histological alterations in the testes and epididymides in mice exposed to 4-nitrophenol by inhalation, while in another study no changes were observed in the reproductive index of pregnant mice given 4-nitrophenol by gavage (placing the chemical experimentally in the stomach).

Cancer Risk

No information is available on the carcinogenic effects of 4-nitrophenol in humans. There was no evidence of carcinogenic activity in mice dermally exposed to 4-nitrophenol for 18 months in a National Toxicology Program (NTP) study. EPA has not classified 4-nitrophenol for potential carcinogenicity.

Safety [5]

First Aid Measures

  • Eye Contact: Check for and remove any contact lenses. Immediately flush eyes with running water for at least 15 minutes, keeping eyelids open. Cold water may be used. Do not use an eye ointment. Seek medical attention.
  • Skin Contact: After contact with skin, wash immediately with plenty of water. Gently and thoroughly wash the contaminated skin with running water and non-abrasive soap. Be particularly careful to clean folds, crevices, creases and groin. Cold water may be used. Cover the irritated skin with an emollient. If irritation persists, seek medical attention. Wash contaminated clothing before reusing.
  • Serious Skin Contact: Wash with a disinfectant soap and cover the contaminated skin with an anti-bacterial cream. Seek immediate medical attention.
  • Inhalation: Allow the victim to rest in a well-ventilated area. Seek immediate medical attention.
  • Serious Inhalation: Evacuate the victim to a safe area as soon as possible. Loosen tight clothing such as a collar, tie, belt or waistband. If breathing is difficult, administer oxygen. If the victim is not breathing, perform mouth-to-mouth resuscitation. Seek medical attention.
  • Ingestion: Do not induce vomiting. Examine the lips and mouth to ascertain whether the tissues are damaged, a possible indication that the toxic material was ingested; the absence of such signs, however, is not conclusive. Loosen tight clothing such as a collar, tie, belt or waistband. If the victim is not breathing, perform mouth-to-mouth resuscitation. Seek immediate medical attention.

Exposure Controls & Personal Protection

Engineering Controls

Use process enclosures, local exhaust ventilation, or other engineering controls to keep airborne levels below recommended exposure limits. If user operations generate dust, fume or mist, use ventilation to keep exposure to airborne contaminants below the exposure limit.

Personal Protective Equipment

The following personal protective equipment is recommended when handling 4-nitropheonal:

  • Splash goggles;
  • Lab coat;
  • Dust respirator (be sure to use an approved/certified respirator or equivalent);
  • Gloves

Personal protective equipment in case of a large spill:

  • Splash goggles;
  • Full suit;
  • Dust respirator;
  • Boots;
  • Gloves;
  • A self-contained breathing apparatus should be used to avoid inhalation of the product.
  • Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling this product.

Regulation [4,6]

United States

  • No occupational exposure limits have been established for 4-Nitrophenol. This does not mean that this substance is not harmful. Safe work practices should always be followed.
  • It should be recognised that 4-Nitrophenol can be absorbed through your skin, thereby increasing your exposure.
  • Environmental Protection Agency (EPA) says that industry must tell the National Response Centre when 100 pounds or more of 4-nitrophenol have been disposed of.