Wood preservation facilities, alkaline copper quaternary: chapter G-4

4. Human Health Concerns

Ammonia and copper are found naturally in food, water and air. Table 4.0 provides estimated daily intakes of these elements by the general population (23).

One safety objective of the industrial use of any chemical (in this case ammoniacal copper, amine copper or quat) is to minimize worker exposure, ideally so that natural intake levels are not exceeded. If safeguards are not provided or are not implemented, a variety of human health effects can occur depending on the duration and manner of exposure, the concentration of the chemical, the form of the chemical (valence), and the varying metabolic sensitivities of individual workers.

The data in Tables 4.0 to 4.3 outline the possible human health effects that may result from exposure to ACQ and its components.

The American Conference of Governmental Industrial Hygienists (ACGIH) does not provide a recommended limit for ACQ, as such. For skin and eye contact with individual components of ACQ, the ACGIH provides the following comments (24):

• A threshold limit value (TLV) of 18 mg/m³ (25 ppm) ammonia has been selected to protect against irritation to eyes and the respiratory tract and to minimize discomfort in unaccustomed workers. A short-term exposure limit of 24 mg/m³ (35 ppm) is suggested.
• A TLV of 7.5 mg/m³ (3 ppm) ethanolamine has been selected to protect against irritation to eyes and the respiratory tract. A short-term exposure limit of 15 mg/m³ (6 ppm) is suggested.
• A TLV of 1 mg/m³ (inhalable particulates) for copper has been established, and is based on inhalation.
• Adequate skin, inhalation and eye protection is required during handling of quat. A TLVfor quat has not been established.

Table 4, which is based on information from existing literature, outlines the spectrum of human health effects that could result from various degrees of exposure to ACQ, to amine copper concentrate, to quaternary ammonium concentrate and to ammonium hydroxide concentrate.