Creosote

2021-06-25

Creosote is the name used for a variety of products: wood creosote, coal tar creosote, coal tar, coal tar pitch, and coal tar pitch volatiles. These products are mixtures of many chemicals created by high-temperature treatment of beech and other woods, coal, or from the resin of the creosote bush. [1]

Wood creosote is a colourless to yellowish greasy liquid with a characteristic smoky odour and sharp burned taste. It is relatively soluble in water. Creosote prepared from coal tar is the most common form of creosote in the workplace and at hazardous waste sites in the United States. Coal tar creosote is a thick, oily liquid that is typically amber to black in colour. It is easily set on fire and does not dissolve easily in water. Coal tar and coal tar pitch are the by-products of the high-temperature treatment of coal to make coke or natural gas. They are usually thick, black or dark brown liquids or semisolids with a smoky or aromatic odour. Chemicals in the coal tar pitch can be given off into the air as coal tar pitch volatiles when coal tar pitch is heated. [2]

Uses [3]

Wood creosote has been used as a disinfectant, a laxative, and a cough treatment, but is rarely used these ways today in the United States. It is still available as an herbal remedy, and is used as an expectorant and a laxative in Japan. Coal tar creosote is the most widely used wood preservative in the United States. It is also a restricted use pesticide and is found in medicines used to treat skin diseases such as psoriasis. Because of the current widespread use of coal tar creosote as a wood preservative and its past pesticidal applications, it is the form of creosote most likely to be present at hazardous waste sites and landfills. Coal tar, coal tar pitch, and coal tar pitch volatiles are used in several industries, including road-paving, roofing, aluminium smelting, and coking.

Sources & Routes of Exposure

Sources of Exposure [4]

General Populations

  • The general population will only be exposed to creosote at low levels. Coal tar creosote is restricted for use to certified applicators only.
  • Potential sources of exposure to creosote include contact with creosote-treated wood products, incineration of creosote-treated scrap lumber, or ingestion of contaminated ground water.
  • Exposure may also occur during the therapeutic use of coal tar dandruff shampoos, coal tar ointments for treatment of eczematous dermatitis or psoriasis.
  • Exposure may also occur through ingestion of dietary supplements or tea that contains leaves from the creosote bush.

Occupational Populations

  • Individuals who work in the wood-preserving industry make up the largest percent of the population that might be exposed to coal tar creosote.
  • Exposure to coal tar pitch and coal tar pitch volatiles may occur in asphalt workers; rubber, aluminium, iron, steel and tire factory workers; and in coke-producing industries.

Routes of Exposure [4]

The routes of exposure to creosotes are as follows:

  • Inhalation – Minor route of exposure for the general population. Predominant route of occupational exposure.
  • Oral – Major route of exposure for the general population.
  • Dermal – Major route of exposure for the general and occupational populations

Health Effects [5]

Acute Effects

Creosote has been involved in incidental or accidental poisoning incidents, mainly due to its use as a pesticide. Deaths occurred following ingestion of about 1 to 2 g (children) or about 7 g (adults). Symptoms included salivation, vomiting, respiratory difficulties, vertigo, headache, loss of pupillary reflexes, hypothermia, cyanosis, convulsion accompanied by oropharyngeal, intestinal, pericardial, liver and kidney damage.

Contact with creosote or creosote vapour may cause irritation of the skin. The skin may become red, papular, vesicular or ulcerated, depending on the period of exposure. Increased photosensitisation may occur, particularly on the face or hands. Vapours and contact can produce an intense burning of the membranes of the eyes and respiratory tract. Eye contact can lead to conjunctivitis and keratitis. One or more of the following effects may be evident on short-term exposure to high concentrations of creosote:

  • systemic – nausea and vomiting, diarrhoea, anorexia and difficulty in swallowing, salivation, abdominal discomfort, respiratory distress, cyanosis, pupillary changes, convulsive movements, rapid pulse or vascular collapse;
  • neurological – headaches, fainting, vertigo and mental disturbances.

Chronic Effects

Chronic exposure may provide sufficient absorption to show the systemic effects listed above.

Carcinogenicity

Increased risks of developing lip and skin cancers have been observed in cohort studies of Swedish and Norwegian wood impregnators and in Finnish round timber workers. A cohort study examining 922 Swedish and Norwegian wood impregnators from 13 plants (for example railroad cross ties and telegraph poles) found a standardised incidence ratio (SIR) of 250 for lip cancers and an SIR of 237 for non-melanoma skin cancer. The risk increased with the latency; analysis by duration of exposure was not provided. According to the authors, the significantly elevated risk for lip and skin cancer could probably be attributed to the combination of exposure to creosote and sunlight. In a population-based record linkage study in Finland, elevated risks for lip cancer, SIR = 306, and non-melanoma skin cancer, SIR = 464, were found for round-timber workers [5]; the mortality for cancer of the scrotum was elevated among brick makers exposed to creosote. Prolonged skin exposure to soot and coal tar creosote has been associated with cancer of the scrotum in chimney sweeps.

Single epidemiological studies suggested a possible risk for bladder cancer, multiple myeloma, and lung cancer due to exposure to creosote. Two case-control studies suggested an increased risk of brain tumours and neuroblastoma among offspring of male workers with possible creosote exposure.

All of the epidemiological studies were based on qualitative estimations of exposure rather than on measurements. There is consistent evidence from human studies that creosote causes skin cancer, but the studies do not allow dose-response analysis.

Creosote, from distillation of coal tar, is classified according to the GHS as Carcinogenicity Category 1B (May cause cancer).

Safety

First Aid Measures

  • Skin: Wash thoroughly with waterless hand cleaners, olive oil or soap and water. Avoid solvents.
  • Eyes: Flush eyes immediately with large amounts of water or olive oil for at least 15 minutes. Call a physician
  • Inhalation: Remove to fresh air. If not breathing, give artificial respiration; preferably mouth-to-mouth. If breathing is difficult, give oxygen. Call a physician.
  • Ingestion: If conscious, first induce vomiting, then take 2 tablespoons of activated charcoal (USP drug grade) in water. Get immediate medical attention. Do not induce vomiting, or give anything by mouth to an unconscious person.

Exposure Controls & Personal Protection

Engineering Controls

Use in areas with adequate natural or local exhaust ventilation.

Personal Protective Equipment

The following personal protective equipment should be used when handling creosotes:

  • Skin Protection: Avoid skin contact whenever possible by using non-porous type gloves. For outdoor work use a waterproof sunscreen (SPF 25 or greater); reapply every 90 minutes while in direct sun. For exposed skin, use protective creams (for example: MSA’s Fend AE-2, Kerodex 51, Jergens SBS-46).
  • Eye Protection: Safety glasses, goggles and/or face shield.
  • Respiratory Protection: Not required for properly ventilated areas. Use a NIOSH approved respirator with suitable organic vapor cartridge as necessary to control exposures above the TLV of PEL.
  • Additional Recommendations: Do not take contaminated work clothing home. It is recommended that a complete soap and water shower and/or steam bath be taken at the end of each working day.

Regulation [2,7]

United States

OSHA: The Occupational Safety and Health Administration has set an exposure limit of 0.2 milligrams of coal tar pitch volatiles per cubic metre of air (0.2 mg/m3) in the workplace during an 8-hour workday, 40-hour workweek.

ACGIH: The American Conference of Governmental Industrial Hygienists recommends the same level for coal tar pitch volatiles.

NIOSH: The National Institute for Occupational Safety and Health recommends a maximum level of 0.1 mg/m3 of coal tar pitch volatiles for a 10-hour workday, 40-hour workweek.

EPA: The Environmental Protection Agency requires that spills or accidental releases into the environment of 1 pound or more of creosote be reported to the EPA.

Australia

Safe Work Australia: Safe Work Australia has established a time weighted average (TWA) concentration for coal tar pitch of 0.2 mg/m3 for a 40-hour workweek.

References

http://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=65&tid=18

http://www.atsdr.cdc.gov/phs/phs.asp?id=64&tid=18

https://www.vdh.virginia.gov/Epidemiology/DEE/publichealthtoxicology/documents/pdf/creosote.pdf

http://www.atsdr.cdc.gov/toxguides/toxguide-85.pdf

http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CC4QFjAB&url=http%3A%2F%2Fwww.safeworkaustralia.gov.au%2Fsites%2FSWA%2Fabout%2FPublications%2FDocuments%2F796%2FCREOSOTE.docx&ei=fCM6U7OHCoGbkgWyq4CABA&usg=AFQjCNGlNDmxY759SSU-M-5jiaoyVTAHNQ&bvm=bv.63934634,d.dGI

http://www.amsa.gov.au/environment/maritime-environmental-emergencies/national-plan/Supporting-Documents/documents/CREOSOTE%20MSDS.pdf

http://www.safeworkaustralia.gov.au/sites/SWA/about/Publications/Documents/772/Workplace-exposure-standards-airborne-contaminants.pdf