Phenol

2021-10-22

Phenol, also known as carbolic acid and phenic acid, is an organic compound with the chemical formula C6H5OH. [1] Pure phenol consists of white or clear acicular crystals. At 41 degrees Celsius, phenol congeals into a solid that can be liquefied by mixing a very small amount of water (2 parts water: 23 parts phenol). On exposure to air and light, phenol assumes a pinkish or reddish discoloration; this discoloration is accelerated by the presence of alkalinity or impurities. Phenol has a characteristic sweet, medicinal, or tar-like odour. [2] It is mildly acidic, but requires careful handling due to its propensity to cause burns. Phenol was first extracted from coal tar, but today is produced on a large scale (about 7 billion kg/year) using a series of industrial processes starting with crude oil. [1]

Uses [3]

Phenol is used as a general disinfectant, as a reagent in chemical analysis and for the manufacture of artificial resins, medical and industrial organic compounds and dyes. It is also used in the manufacture of fertilisers, explosives, paints and paint removers, drugs, pharmaceuticals, textiles and coke. It is produced in large volume, mostly as an intermediate in the production of other chemicals. The largest single use of phenol is as an intermediate in the production of phenolic resins, which are low-cost, versatile, thermoset resins used in the plywood adhesive, construction, automotive, and appliance industries. It is also used as an intermediate in the production of caprolactam, which is used to make nylon and other synthetic fibres, and bisphenol A, which is used to make epoxy and other resins.

Sources of Emission and Routes of Exposure

Sources of Emission [3]

  • Industry sources: Phenol is a common component of oil refinery wastes. It is also produced in the conversion of coal into gaseous or liquid fuels and in the production of metallurgical coke from coal. It may enter the environment from oil refinery discharges, coal conversion plants, municipal waste treatment plant discharges, or spills.
  • Diffuse sources: Released as a vapour from natural or human made sources contaminated by or containing phenol.
  • Natural sources: Phenol is found naturally in animal wastes and decomposing organic material.
  • Consumer products: Agricultural chemicals, disinfectants (non-agricultural), general antibacterials and antiseptics, household hard surface cleaners (liquid), lubricating oils, automotive chemicals, paint and varnish removers, pharmaceutical preparations, synthetic resin and rubber adhesives, wood office work surfaces (modular systems).

Routes of Exposure [2]

Exposure to phenol can occur via the following routes:

  • inhalation,
  • ingestion,
  • eye or skin contact, and
  • absorption through the skin

Health Effects [4]

Acute Effects

Inhalation and dermal exposure to phenol is highly irritating to the skin, eyes, and mucous membranes in humans. Symptoms of acute toxicity in humans include irregular breathing, muscle weakness and tremors, loss of coordination, convulsions, coma, and respiratory arrest at lethal doses. Acute animal tests in rats, mice, and rabbits have shown phenol to have high acute toxicity from oral exposure.

Chronic Effects

Anorexia, progressive weight loss, diarrhoea, vertigo, salivation, and a dark coloration of the urine have been reported in chronically exposed humans. Gastrointestinal irritation and blood and liver effects have also been reported. In one study, muscle pain, weakness, enlarged liver and elevated levels of liver enzymes were found in an individual after inhalation and dermal exposure to phenol and a few other chemicals. Application of phenol to the skin results in dermal inflammation and necrosis. Cardiac arrhythmias have also been reported in humans exposed to high concentrations of phenol. Chronic inhalation exposure of animals to phenol has shown central nervous systems (CNS), kidney, liver, respiratory, and cardiovascular effects. The Reference Dose (RfD) for phenol is 0.6 milligrams per kilogram body weight per day (mg/kg/d) based on reduced foetal body weights in rats. EPA has established a provisional Reference Concentration (RfC) for phenol of 0.006 milligrams per cubic metre (mg/m3) based on no effects in rats, mice, or monkeys.

Reproductive/ Developmental Effects

No studies were located concerning the developmental or reproductive effects of phenol in humans. Animal studies have reported reduced foetal body weights, growth retardation, and abnormal development in the offspring of animals exposed to phenol by the oral route. Decreased maternal weight gain and increased maternal mortality were also observed.

Cancer Risk

Small, non-significant excesses in certain types of cancers were reported in occupationally exposed workers; however, these effects were not clearly related to phenol exposure. Animal studies have not seen tumours resulting from oral exposure to phenol, while dermal studies have reported that phenol applied to the skin may be a tumour promoter and/or a weak skin carcinogen in mice. EPA has classified phenol as a Group D, not classifiable as to human carcinogenicity, based on a lack of data concerning carcinogenic effects in humans and animals.

Safety [5]

First Aid Measures

  • Eye Contact: Check for and remove any contact lenses. In case of contact, immediately flush eyes with plenty of water for at least 15 minutes. Cold water may be used. Get medical attention immediately.
  • Skin Contact: In case of contact, immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Cover the irritated skin with an emollient. Cold water may be used. Wash clothing before reuse. Thoroughly clean shoes before reuse. Get medical attention immediately.
  • Serious Skin Contact: Wash with a disinfectant soap and cover the contaminated skin with an anti-bacterial cream. Seek immediate medical attention.
  • Inhalation: If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical attention immediately.
  • 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: If swallowed, do not induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an unconscious person. Loosen tight clothing such as a collar, tie, belt or waistband. Get medical attention immediately.

Fire Hazard Data

Phenol may be combustible at high temperature. It is flammable in the presence of open flames and sparks, of heat. Non-flammable in presence of shocks, of oxidising materials, of reducing materials, of combustible materials, of organic materials, of metals, of acids, of alkalis. A dry chemical powder should be used to extinguish small fires. Foe large fire, use water spray, fog or foam. Do not use water jet.

Exposure Controls & Personal Protection

Engineering Controls

Provide exhaust ventilation or other engineering controls to keep the airborne concentrations of vapours below their respective threshold limit value. Ensure that eyewash stations and safety showers are proximal to the work-station location.

Personal Protection

The following personal protective equipment is recommended when handling phenol:

  • Face shield
  • Full suit
  • Vapour respirator (be sure to use an approved/certified respirator or equivalent)
  • Gloves
  • Boots

Personal Protection in Case of a Large Spill:

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

Regulation [2,3,6]

United States

  • OSHA: The current Occupational Safety and Health Administration permissible exposure limit (PEL) for phenol is 5 ppm (19 milligrams per cubic metre (mg/m3) as an 8-hour time-weighted average (TWA) concentration. In addition, the OSHA PEL bears a “Skin” notation, which indicates that the cutaneous route of exposure (including mucous membranes and eyes) contributes to overall exposure [29 CFR 1910.1000, Table Z-1].
  • NIOSH: The National Institute for Occupational Safety and Health has established a recommended exposure limit (REL) for phenol of 5 ppm (19 mg/m3) as a TWA for up to a 10-hour workday and a 40-hour workweek and a short-term exposure limit (STEL) of 15.6 ppm (60 mg/m3) for periods not to exceed 15 minutes. NIOSH also assigns a “Skin” notation to phenol [NIOSH 1992].
  • ACGIH: The American Conference of Governmental Industrial Hygienists has assigned phenol a threshold limit value (TLV) of 5 ppm (19 mg/m3) as a TWA for a normal 8-hour workday and a 40-hour workweek. The ACGIH also assigns a “Skin” notation to phenol [ACGIH 1994, p. 29].
  • EPA: The Environmental Protection Agency has determined that exposure to phenol in drinking water at a concentration of 6 milligrams per litre (mg/L) for up to 10 days is not expected to cause any adverse effects in a child. A lifetime exposure to 2 mg/L phenol in drinking water is not expected to cause any adverse effects.
  • FDA: The Food & Drugs Administration has determined that the phenol concentration in bottled drinking water should not exceed 0.001 mg/L.

Australia

  • Safe Work Australia has established a maximum 8 hour time weighted average (TWA) of 1 ppm (4 mg/m3)

References

https://en.wikipedia.org/wiki/Phenol

https://www.osha.gov/SLTC/healthguidelines/phenol/recognition.html

http://www.npi.gov.au/substances/phenol/index.html

http://www.epa.gov/ttn/atw/hlthef/phenol.html

http://www.sciencelab.com/msds.php?msdsId=9926464

http://www.atsdr.cdc.gov/PHS/PHS.asp?id=146&tid=27#bookmark04