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

penta
 

arsenicals
creosote 

copper naphthenate

Identity And Uses

Ingredients, including contaminants, inerts, and by-products

Copper naphthenate is a copper salt of naphthenic acid. Naphthenic acid is a complex natural mixture of fatty acids found in petroleum. It is a by-product of petroleum refining and has a variable composition.1 Ingredients, including contaminants, inerts, and by-products A typical copper naphthenate product would be about 19% copper naphthenate and 81% secret ingredients.2 The copper naphthenate portion is itself poorly characterized. Its composition depends on the composition of the source petroleum. The naphthenic acids may contain such constituents as cyclopentylacetic acid, alkyl-substituted cyclopentylacetic acids, fused chains of cyclopentylacetic acids, cyclohexylacetic acids, cyclopentanoic acids, and various low-molecular-weight fatty acids.3 It may also be contaminated up to 25% with hydrocarbons such as benzene from the petroleum source.4 

Trade names

Cuprinol, Wittox-C, Osmose Cop-R-Nap. 

Usage

US production in 1988 was 3.4 million pounds.5 900,000 pounds were used in wood preservation in 1975.6 
Toxicology 

The toxicology of copper naphthenate has not been well documented. EPA reports that little of the required data has been submitted--very little acute toxicity data, no chronic toxicity data, and no inhalation data. Similarly, the Canadian Centre for Occupational Health and Safety has no information for most health effects of copper naphthenate.7 

Absorption

Little is reported. However, one study of a family living in a home with a foundation treated with copper naphthenate speculated that the increased blood levels of copper may have arisen from copper volatilized by the copper naphthenate formulation.8 

Clearing, detoxification, and metabolism

Copper is generally cleared from the body unless in acutely toxic quantities. It is stored in the liver and marrow.9 

Acute toxicity

Inhalation of copper salts in dusts can lead to congestion of nasal membranes, congestion of the upper digestive, and perforation of the nasal septum. Very high concentrations can cause extreme symptoms of irritation.10 Very little information is available about the toxicity of naphthenic acids.Although as much as 25% of copper naphthenate may be hydrocarbon contaminants from petroleum, we know very little about these contaminants, except that they are variable in identity and quantity. Petroleum does contain many acutely toxic, chronically toxic, and carcinogenic compounds such as benzene, however, and we must assume that some of them are present in copper naphthenate. 

Critical doses

EPA does not have enough information to establish a LD50 (lethal dose for half of the test population). 

Chronic health effects

Chronic exposure to copper salts may result in anemia.11 Exposure to naphthenic acids increases the permeability of membranes, which could increase uptake of other toxic substances.12 Although as much as 25% of copper naphthenate may be hydrocarbon contaminants from petroleum, we know very little about these contaminants, except that they are variable in identity and quantity. Petroleum does contain many acutely toxic, chronically toxic, and carcinogenic compounds such as benzene, however, and we must assume that some of them are present in copper naphthenate. We also know nothing about the effects of the secret ingredients that make up 80% of copper naphthenate products. 

Organ damage 

Both copper salts and naphthenic acids are skin irritants. 

Neurotoxicity

Exposure to naphthenic acids increases the permeability of membranes to potassium, which could affect nerve transmission.13 Although as much as 25% of copper naphthenate may be hydrocarbon contaminants from petroleum, we know very little about these contaminants, except that they are variable in identity and quantity. Petroleum does contain neurotoxic compounds such as benzene, however, and we must assume that some of them are present in copper naphthenate. 

Reproductive toxicity and teratogenicity

No data. 

Immunotoxicity

No data. 

Critical doses

EPA has not set levels because of inadequate information. 

Cancer

Chronic exposure to copper salts has produced lung and liver damage which sometimes progressed to cancer.14 

Mutations

Tests submitted to EPA found copper naphthenate induces DNA damage.15 

Endocrine disruption

No data. 

Ecological Effects

Bioaccumulation/bioconcentration potential

Except in extreme exposure conditions, excess copper is cleared from organisms. Mollusks accumulate more naphthenic acids than less toxic components of oil.16 

Leaching potential and environmental fate

Copper salts have been found to leach from wood treatment sites. More leaches under acidic conditions.17 No data is available on the environmental fate of naphthenic acids. 

Ecotoxicity

Copper naphthenate is toxic to a wide variety of organisms. It kills microorganisms, fungi, and plants.18 It is toxic to aquatic life--including invertebrates, algae, and fish--in very low concentrations.19 Naphthenic acids reduced the fertility of sturgeon roe and the survivability of adults.20