Principal administration of the preservative treatment of timber in New Zealand is by the Timber Preservation Authority (TPA). The TPA was established in 1955 by Act of Parliament and is under the jurisdiction of the Minister of Forests who appoints its members. Its field staff are Forest Service employees. The Authority comprises twelve members and includes representatives of timber trade associations and state, local body and professional organisations who have an interest in preservative treatment and timber usage. The TPA has sole discretion in approving types of preservatives, treatment processes and standards of treatment within New Zealand. Standards of treatment of timber and timber products imported for use in the country must also meet TPA requirements. Application for licence to treat timber is made through the TPA. The applicant must provide evidence as to the efficiency and suitability of the proposed preservative treatment. He must also satisfy the Authority that he is capable of instituting and maintaining a control of preservative treatment by way of processes, inspections and tests which will ensure that every treatment will comply with regulations prescribed by the TPA. These are published in the TPA Specifications, which are mandatory for all commercially treated timber and composite timber products. Specifications stipulate approved processes, preservatives and their retentions in the various commodities treated, and the identification, by branding, of the treated timber offered for sale. There are approximately 300 authorised treatment plants in New Zealand of which 160 are vacuum pressure plants using copper/chrome/arsenic preservatives. The remainder are boron diffusion plants plus three Rueping plants. Details of all treatment charges must be entered on appropriate forms and copies forwarded each month to the Senior TPA Officer. In addition, each full cell vacuum/pressure plant must forward a monthly preservative usage reconciliation statement. Plants may be inspected by TPA field personnel at any time and samples of preservative solutions and treated timber may be removed for analysis to check compliance with Specifications. The TPA has power to revoke or suspend authorisation of treatment plants which do not meet prescribed standards of treatment. Although the TPA has exclusive control over Standards of treatment, other state departments or legislation may from time to time influence aspects of preservative use. The Department of Labour has authority to promulgate regulations or issue recommendations concerned with the safety of personnel who are exposed to the possible toxic effects of wood preservatives. The Department of Health has jurisdiction over the registration and use of all classes of poisons within New Zealand. It has authority to proscribe the use of any chemical which it considers is abnormally hazardous in the use to which it is put. In this respect, the Department of Health has supreme power to revoke approval of any wood preservative used in New Zealand. Regulations governing the use of all pesticides are contained in a bill currently before the New Zealand parliament. The bill is mainly concerned with those pesticides which are available to the casual purchaser. Although it is unlikely that any Act of Parliament based on this bill would affect commercial timber treatment, the use of certain chemicals by remedial treatment firms, chiefly for borer control, may be restricted. Those chemicals used as prophylactics during seasoning and preservatives purchased for home and farm timber treatments may be included within the scope of the bill.

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