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Poison Poles - A Report About Their Toxic Trail and Safer Alternatives Appendix A: Chemicals-At-A-Glance

Creosote

penta 
arsenicals
creosote 

copper naphthenate 

Identity And Uses 

Ingredients, including contaminants, inerts, and by-products

Creosote is a complex mixture of many chemicals. There are three kinds of creosote. One type results from high-temperature treatment of coal (coal tar creosote), one results from high-temperature treatment of beech and other woods (beechwood creosote), and one comes from the resin of the creosote bush (creosote bush resin). Coal-tar creosote is the most widely used wood preservative in the United States. About 300 chemicals have been identified in coal-tar creosote, and there may be 10,000 other chemicals present in the mixture. The major chemicals in coal-tar creosote that can cause harmful health effects are polycyclic aromatic hydrocarbons (PAHs), phenol, and cresols.1 Coal-tar creosote is usually a heavy, oily, liquid containing mainly alkylnaphthalenes, naphthalene, diphenyl, acenaphthalene, fluorene, plus small amounts of higher phenols, diphenylene oxide, quinoline base and indole. It is typically amber to brown in color, burns easily, but does not dissolve readily in water.2 Some parts of the creosote mixture can enter groundwater or change into other substances while other parts persist in treated wood products for decades.3 

Trade names

P1/P13 Creosote, Timberlife Wood Preserving Compound 

Usage

In 1995: 92,000,000 gallons;4 8,941,000 cubic feet of treated poles; 91,751,000 cubic feet of treated wood.5 

Toxicology

Absorption

Creosote can enter the body through the lungs as a contaminant of air, through the stomach and intestines after eating contaminated food or drinking contaminated water, or through the skin. Many of the components of the creosote mixture (for example, PAHs) are rapidly absorbed through the lungs, stomach and the intestines. Eating soil contaminated with coal-tar creosote can also provide a source of exposure. Chemicals in coal-tar creosote appear to accumulate in the body, particularly in fat tissue.6 

Clearing, detoxification, and metabolism

Most of the chemicals in creosote that are taken into the body are not stored in the body tissues, and leave in the feces within a few days.7 

Acute toxicity

Reports describing coal-tar creosote poisoning in workers or accidental or intentional ingestion of coal-tar creosote indicate that brief exposures to large amounts of coal-tar creosote can cause harmful effects on the skin, eyes, nervous system, and kidneys; produce abdominal pain and vomiting, heart damage, anemia, and can result in death. Skin contact with a few drops of coal-tar creosote irritates and burns the skin and eyes. Coal-tar creosote also makes the skin more sensitive to the effects of the sun. These effects include burning, irritation and swelling.8 9 When heated to decomposition it emits acrid smoke and fumes, which may cause irritation of eyes, nose and throat.10 

Critical doses

Short-term and long-term studies with animals have shown similar effects from exposure to cresols.11 

Chronic health effects

Organ damage 

Longer-term exposure to lower levels of coal- tar creosote can also result in damage to skin, such as reddening, blistering or peeling. The major organs or systems affected by longer-term exposure to lower levels of coal-tar creosote in animals are the skin and lungs.12 

Reproductive toxicity and teratogenicity

Experiments in rats and mice have shown creosote to be teratogenic.13 Birth defects have been seen in livestock exposed to wood treated with coal-tar creosote.14 

Immunotoxicity

Evidence in both animals and humans suggests that arsenic suppresses the immune system.9 

Critical doses

A dose of 143 milligrams per kilgrams per day results in an increase in relative brain weight in rats. 

Cancer

An increased risk for cancer has been demonstrated in animals exposed to coal-tar creosote. The International Agency for Research on Cancer has determined that creosote is probably carcinogenic to humans (Group 2A).15 The Environmental Protection Agency (EPA) has determined that cresols are possible human carcinogens.16 Animal studies show that cresols may increase the ability of some carcinogenic chemicals to cause tumors.17 Dermal exposure to creosote can increase the risk of cancer from other agents.18 

Mutations

Creosote has been shown to be mutagenic in human studies.19 

Endocrine disruption

Creosote contains ingredients, benzo(a)pyrene and higher phenols, considered to be endocrine disruptors.20 

Ecological Effects 

The major source of creosote in surface waters and groundwater is waste water from wood preserving facilities.21 

Bioaccumulation/bioconcentration potential

Some creosote components are taken up by plants to a limited extent. More commonly, they adsorb to plant roots. Both terrestrial and aquatic animals have been observed to bioconcentrate creosote components.22 

Leaching potential and environmental fate

Some components of creosote (for example, phenols and nitrogenous bases such as aniline, toluidines and xylidines) are water soluble. They migrate easily from contaminated soils or poles. Usually polycyclic aromatic hydrocarbons are strongly attached to soil particles (and may move with sediments into streams) or remain part of a tarlike mass, but they may move into groundwater in sandy soils low in organic matter. The remaining phenolic and heterocyclic components, as well as lighter polycyclic aromatic hydrocarbons, near the soil surface are generally volatilized, oxidized, or biodegraded. While many components are biodegraded, the high molecular weight polycyclic aromatic hydrocarbons that remain are bioaccumulative and carcinogenic.23 

Ecotoxicity

Hepatic lesions and neoplasms in fish have been associated with exposure to creosote contaminated water.24 
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