Wood preservation facilities, copper azole : chapter H-6

6. Protection of Personnel

Electronic copies of the pesticide labels for all registered CA-B products, which contain information on product handling precautions, minimum worker protective equipment and health hazard warnings, can be obtained on the Health Canada website (3). The conditions of use specified on the pesticide label are mandatory by law. Ensure that the information on the most current product label is followed.

6.1 First Aid Precautions and Hygiene for CA-B Exposure

A summary of the first aid measures listed in Table 5 should be available on-site, preferably in the same location as the first aid material. For all medical attention, always take the pesticide label to show to the health personnel.

Table 5 outlines first aid measures for exposure to CA-B and its constituents.

When exposure to a chemical occurs, the severity and speed of damage to human health depends on the concentration. The general rule for dealing with exposure is as follows: the higher the concentration of a preservative to which a worker is exposed, the greater the need for protective measures and immediate response if contact occurs. If there is any doubt as to the concentration, the response should be the same as for the most concentrated form. Immediate response is required if a worker is exposed to CA-B concentrate solutions.

Artificial respiration should not be performed without the use of a barrier device, as the injured person may be contaminated (on skin) with CA-B solution, making the first aider the next victim if direct mouth-to-mouth contact is made.

Facility staff should have access to product labels and appropriate training to apply first aid.

Personnel should follow the recommendations from Table 6 of Chapter A outlining general precautions and personal hygiene measures.

6.2 Regulatory Controls

The label for pesticide product contains information on the minimum necessary protective equipment and practices for using the product. The worker protection measures on the pesticide label are mandatory. Provincial or municipal regulations may require additional measures that may enhance, but not reduce, protection. Table 7 in Chapter A can be used to summarize the local regulatory threshold limit values (TLVs) and/or biological exposure indices (BEIs) applicable to the plant.

Specific limits for worker protection are generally prescribed by provincial regulations. Consult your local authorities for specific applicable regulations.

Most of the criteria established by worker protection agencies are based on the TLVs and BEIs recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). The ACGIH limits of exposure in the workplace are specified in Table 4 for copper and ethanolamine only; no limits are provided for tebuconazole.

Skin and Eye Contact

Copper azole, as such, is not discussed by the ACGIH. With reference to skin and eye contact, the ACGIH provides the following conclusion in its support rationale (14) for TLV levels only for copper and ethanolamine: copper salts act as irritants that may produce itchy eczema on skin and conjunctivitis or ulceration of the eye. However, the TLV for copper salts is based on inhalation.These limits may not adequately take into account routes of exposure other than inhalation. The ACGIH has suggested that in such cases, “biological exposure indices may be useful as a guide to safe exposure” (14).

Inhalation

The TLVs stipulated by the ACGIH are those “airborne concentrations of substances to which it is believed that nearly all workers may be repeatedly exposed day after day without adverse effects.” The TLVs for copper (14) are defined in Table 4, with the following provisos of the ACGIH:

• “The limits are intended for use in the practice of industrial hygiene as guidelines for good practices or recommendations in the control of potential health hazards and for no other use” (i.e. proof or disproof of the cause of an existing disease or physical condition).
• “The limits are not fine lines between safe and dangerous concentrations.”
• “In spite of the fact that serious injury is not believed likely as a result of exposure to the Threshold Limit concentrations, the best practice is to maintain concentrations of all atmospheric contaminants as low as is practical.”
• “When two or more hazardous substances, which act upon the same organ system, are present, their combined effect, rather than that of either individually, should be given primary consideration.”

The limits as defined by the ACGIH would apply primarily to suspended aerosols, dusts or gases generated during welding. Generally, airborne contaminants are not generated in CA-B facilities at quantities that would cause significant worker exposure, since CA-B wood preservation facilities use exclusively CA-B water solutions. Though incidental exposures are possible at all facilities, incidents of aerosol exposure would be more probable at improperly maintained facilities (i.e. from leaking seals) or at inadequately designed facilities (e.g. from vacuum pump discharges to the work area). Dust generation is most probable from forklifts and trucks moving on the drip pad and the yard, and is also expected from cleaning operations. Frequent washdowns of pads and collection of the sump contents should minimize airborne contaminants caused by pad traffic.

Ingestion

Oral intake of CA-B must be avoided. Ingestion of liquids containing CA-B liquids is unlikely if workers follow the precautions and personal hygiene measures outlined in Chapter A, Section 6, Table 6. Acceptable limits of ingestion are not prescribed by regulation, since it is generally expected that no such intake will occur.

6.3 Safety Precautions

Workers need to familiarize themselves with the safety precautions mentioned in Chapter A, Section 6.3, Table 8.

Sensitive individuals should take special care to avoid exposure.

6.4 Biological Monitoring of Exposed Workers

Biological monitoring is a useful tool for evaluating the long-term effectiveness of the protective measures applied. Routine biological monitoring of exposed workers (primarily those who handle preservatives and treated wood, e.g., plant operators and quality control personnel) is recommended. Refer to Chapter A, Section 6.4