Wood preservation facilities, ammoniacal copper zinc arsenate: chapter C-4

4. Human Health Concerns

Ammonia, copper, zinc and arsenic are found naturally in food, water and air. Table 4 and Table 4.1 provide estimated daily intakes of these elements by the general population (5, 9, 10, 11). Figure 1 in Section 5.2 - Potential Chemical Discharges indicates where each component can be encountered in the process.

One safety objective for the industrial use of any chemical (in this case, ammonia, copper, zinc or arsenic) is to minimize worker exposure to the chemical, ideally so as not to exceed acceptable intake levels. If safeguards are not provided or implemented, a variety of human health effects may occur depending on the duration and manner of exposure, concentration of chemicals, chemical forms (valence), and varying metabolic sensitivities of individual workers.

The PMRA’s re-evaluation decision for the registration of the heavy duty wood preservatives creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate, has granted continued registration of these products for sale and use in Canada. Potential risks from inhalation and dermal exposure were identified for some occupational tasks within wood-treatment facilities. The addition of new risk-reduction measures and the development of a Risk Management Plan for heavy duty wood preservatives will continue to lower the potential for occupational risks to treatment facility workers (12).

Workers need to familiarize themselves with all current material safety data sheets.

Table 4 and Table 4.1, which is based on information from existing literature, outline the spectrum of human health effects that could result from various degrees of exposure to ACZA and ammonium hydroxide concentrate.