The term “creosote logs” often refers to wood treated with creosote, a substance historically used as a wood preservative to guard against decay and pests. This material, commonly seen in old railroad ties and utility poles, raises understandable concerns about its safety. Understanding the chemical makeup of creosote and the ways it can affect human health provides the necessary context for addressing these toxicity concerns.
Understanding the Chemical Composition and Purpose
Creosote is not a single chemical but a complex mixture of hundreds of compounds derived from the high-temperature distillation of coal tar. This oily liquid ranges in color from yellowish-green to black and possesses a distinct, pungent odor. Its composition is dominated by a class of organic compounds known as Polycyclic Aromatic Hydrocarbons (PAHs), which can constitute over 75% of the total mixture.
The presence of PAHs, such as naphthalene and phenanthrene, is the primary source of creosote’s toxicity and its persistence in the environment. These compounds are particularly resistant to degradation and are known for their harmful health effects.
Coal tar creosote is specifically used as a heavy-duty wood preservative, applied using high-pressure equipment in industrial settings. Creosote’s chemical properties make it highly effective at preventing fungal decay, insect damage, and marine borer infestations. This preservation capability is why it has been historically used for applications like railroad ties, marine pilings, and utility poles.
Specific Health Risks of Exposure
Exposure to creosote-treated wood involves several distinct health risks, primarily related to the toxic PAHs present in the substance. Direct dermal contact is a common route of exposure, leading to immediate and localized reactions. The oily nature of creosote can cause skin irritation, burning sensations, and a noticeable rash.
A specific danger of skin exposure is photosensitivity, where contact with creosote makes the skin highly reactive to sunlight, resulting in severe sunburns or chemical burns. Repeated or prolonged skin contact may also lead to changes in skin pigmentation. If creosote dust or oil contacts the eyes, it can cause severe irritation and potentially result in vision loss.
Inhalation presents another hazard, particularly when creosote-treated wood is cut, sanded, or burned. Breathing in the vapors and aerosols released can irritate the nose, throat, and lungs, leading to acute respiratory problems. Long-term exposure to these fumes and dusts has been linked to chronic respiratory issues, including asthma and chronic bronchitis.
The most serious long-term risk relates to the systemic effects of the PAHs, which are classified as probable human carcinogens. The U.S. Environmental Protection Agency (EPA) and the International Agency for Research on Cancer (IARC) base this classification on sufficient evidence from animal studies and limited evidence from human occupational exposure, linking long-term skin contact to an increased risk of skin and scrotal cancer. The carcinogenic compounds can also be absorbed through the skin, increasing the overall body burden.
Practical Guidelines for Handling and Disposal
Working with creosote-treated wood requires specific precautions to mitigate the risks of exposure. When moving, cutting, or otherwise handling these materials, it is necessary to wear personal protective equipment (PPE) to create a barrier against the oily residue and dust. This PPE should include gloves that are impervious to the chemicals, such as vinyl-coated options, and long-sleeved shirts and long pants to prevent direct skin contact.
If sawing or machining the wood, a dust mask or respirator is needed to avoid inhaling sawdust, and goggles should be worn to protect the eyes. All exposed skin areas must be washed thoroughly after working with the wood, and before eating, drinking, or using tobacco products. Work clothes that have accumulated oil or sawdust should be laundered separately from other household clothing.
A strict prohibition exists against burning creosote-treated wood in residential settings, including fireplaces, wood stoves, or open bonfires. Burning this wood releases toxic chemicals into the smoke and ash, which poses an inhalation risk to occupants and the surrounding environment. Only commercial or industrial incinerators, which are specifically regulated, may burn this material.
The disposal of creosote-treated wood must also be handled carefully, as it cannot typically be treated as standard yard waste. While the EPA indicates that homeowners can often dispose of it as municipal solid waste, many state and local jurisdictions classify it as a special waste. It is essential to check with a local waste management program to determine the approved disposal method, which may include permitted landfills or specialized hazardous waste collection facilities.