Health hazards of natural and introduced chemical components of boatbuilding woods.

The major components of untreated wood--cellulose, hemicellulose, and lignin--have not been implicated as toxicants, but extractive substances, especially in heartwood, can be toxic. Decay-resistant woods are more likely to contain irritants or sensitizers than nondurable woods. Short-term exposures to certain wood dusts may result in asthma, conjunctivitis, rhinitis, or allergic dermatitis, but long-term effects may include nasal cancer and Hodgkin's disease. Some thermophilic microorganisms found in wood are human pathogens, and septic splinters (chromomycosis) and inhalation of ascomycete spores from stored wood chips have been implicated in human illnesses. Reconstituted wood can contain formaldehyde resins, which pose health risks in enclosed humid areas. Pentachlorophenol (PCP)-treated wood is particularly toxic--short-term exposures to PCP-treating solutions can lead to aplastic anemia and mortality, while diseases such as Hodgkin's disease are associated with long-term exposures. Since much commercial lumber is dipped in PCP, the separation of the chronic effects of wood dust from PCP exposure is difficult. Chromated copper arsenate (CCA)- and ammoniacal copper arsenite (ACA)-treated wood may leach arsenic. CCA-treated wood is potentially safer, since it contains the pentavalent arsenic, which is a common constituent in the environment. ACA contains the trivalent arsenic, which is more toxic.