Environmental recommendations for wood preservation facilities: foreword


Colourful forest landscape and a lake from Est Canada.

Photo: © Environment Canada 2014

Wood exposed outdoors is subject to degradation by various organisms, including fungi, insects and marine borers. The impregnation of wood with preservative chemicals retards or prevents its destruction by these agents. By design, such preservative chemicals must be toxic to the target organisms. However, their use may also affect non-target biota and the environment, unless proper safeguards are taken. Like many other industrial chemicals, wood preservatives require proper handling to prevent hazards in the workplace and during transportation and storage, as well as to avoid emissions from the process and the treated product.

In 1984, Environment Canada, as part of a federal strategy to protect the environment and human health from potentially toxic commercial chemicals, evaluated use practices within the wood preservation industry. The Department subsequently initiated a technical steering committee to develop technical recommendations for facility design and operations.

The objectives were to develop recommendations that would outline practices to

  • reduce or eliminate the release of wood preservative chemicals to the environment; and
  • minimize the exposure of workers to wood preservative chemicals.

The development process, which included the participation of representatives from federal and provincial government agencies, the wood preservation industry, forest industry labour unions, and workers’ compensation boards, concluded with the publication of five technical recommendations documents (TRDs) in 1988 (1, 2, 3, 4, 5). The documents covered good practices for pressure treatment with each of the major wood preservatives then in use: chromated copper arsenate (CCA), ammoniacal copper arsenate (ACA), pressure treatment with pentachlorophenol (PCPP), thermal treatment with pentachlorophenol (PCPT) and creosote. These documents have since been widely applied in Canada to the construction of new facilities and the upgrading of existing wood preservation facilities. In addition, international technical guidance documents for the preservation industry have made use of information contained in the Canadian TRDs from 1988 (6, 7, 8).

The measures recommended in the 1988 TRDs were based on knowledge of the existing technology and the properties of the preservative chemicals at the time of their development. However, since the publication of the 1988 TRDs, a variety of new and modified operating technologies have been developed, environmental compliance criteria have changed, and knowledge of the properties of the chemicals has been expanded. Hence, it was deemed necessary to review the TRDs, update information where appropriate, and include any new technologies to take advantage of improved design and operational practices.

In response to the need to update the 1988 TRDs, Environment Canada and the Canadian Institute of Treated Wood (CITW), now known as Wood Preservation Canada (WPC), initiated development of a single revised TRD, which was published in March 1999 (9). A review of the 1988 TRDs was organized by CITW and was undertaken by industry members. The industry comments were compiled by Frido Consulting. Relevant industry information, as well as additional information from the open literature or from experts and regulatory agencies, was also used to update the recommendations. The document underwent four draft stages, each entailing reviews and comments by industry, as well as by federal and provincial regulatory personnel. It was finalized by a technical coordinating committee.

As indicated above, the 1988 recommendations were presented in five comprehensive documents. These have been found to be user-friendly in format and general content. However, there were many subjects and recommendations common to all, leading to duplication. To eliminate such duplication, the 1999 TRD included all preservatives and treatments in a single manual. Although the 1999 manual followed the contents and format of the 1988 TRDs as closely as possible, general background information and recommendations applicable to all preservatives were separated from information specific to individual preservatives. This structure made information about individual preservatives easier to find and facilitates the addition of new preservatives and any other incidental information.

On a parallel track, Environment Canada and Health Canada developed a process for managing environmental toxic contaminants under the Canadian Environmental Protection Act (CEPA).

The process involved identifying CEPA ToxicFootnote1 substances and the development of a risk-management strategy through a Strategic Options Process (SOP). The SOP addresses the releases of CEPA Toxic substances used by the wood preservatives as listed in Table 1:

Table 1: List of CEPA Toxic Substances Used in Wood Preservatives

CEPA Toxic Substance (1999) Wood Preservative

Chromium VI

Inorganic arsenic compounds

Chromated Copper Arsenate (CCA)

Ammoniacal Copper Zinc Arsenate (ACZA)

Polycyclic Aromatic Hydrocarbons (PAHs),

Creosote-impregnated waste materials


Polychlorinated dibenzodioxins (Dioxins)

Polychlorinated dibenzofurans (Furans),

Hexachlorobenzene (HCB)

Pentachlorophenol (PCP)

Following publication of the 1999 manual (1999 TRD) and the SOP report the industry proceeded with a voluntary program to implement the recommendations at all wood preservation facilities in Canada. The goal of the program was to have all facilities adopt the recommendations of the TRD by 2005. To meet this goal, the TRD Implementation Program was developed with the following steps:

  • Two rounds of information sessions were held across Canada to inform wood preservation facilities about the program.
  • A baseline assessment, referred to as Assessment 2000, was conducted at every facility to determine the level of adoption of the TRD.
  • Each facility was required to submit an implementation plan by December 31, 2001, which would describe how it intended to correct deficiencies from Assessment 2000.
  • On December 31 of years 2002 to 2005 inclusive, facilities were required to submit annual update reports to demonstrate continual improvement towards the 2005 goal.
  • Random assessments were conducted to determine whether the implementation plans were executed as intended.

The program generated questions and additional knowledge regarding best management practices. As a result, the 1999 TRD was revised and the 2004 updated document was published.

The 2004 updated manual maintained the format and content of the 1999 version. It included new chapters on the preservatives alkaline copper quaternary (ACQ), copper azole (CA-B) and inorganic boron, which were newly registered in Canada. Ammoniacal copper arsenate (ACA) was replaced by the preservative ammoniacal copper zinc arsenate (ACZA). As well, the manual contained design and operational measures to enable safe operations in wood preservation facilities in terms of worker exposure and health risks as well as environmental impact (10.

Following the December 31, 2005, deadline to adopt the TRDs, final audits of every facility in the voluntary program were conducted to verify the level of adoption of the TRD as part of the SOP-TRDFootnote2 implementation program. A total of 53 facilities were audited from early 2005 until November 2006. The overall range of national adoption of the TRD for all preservative facilities was found to be 59% to 99%, with an average of 87%. At that time, 37 of 53 plants (70%) had adopted at least 99% of the recommendations, with another 10 plants (19%) at an adoption rate of over 95% (10).

As the audit results showed, the targeted 100% adoption rate was not entirely met, in large part due to a lack of information, e.g., for workplace and site monitoring, or due to a lack of medical programs or misinterpretation of TRD requirements. A significant impact on the industry had occurred during the switch from CCA to the new water-borne preservatives for residential applications. Nevertheless, the audits showed that significant progress did occur towards achieving the goals (11). The efforts to meet the requirements of the TRD were significant, with capital expenditures at several individual plants that exceeded $1.5 million. As well, considerable in-house efforts were implemented to upgrade documentation, training and monitoring programs. It can be said that since 2000 there have been significant positive changes made by the industry with regard to operations and monitoring (11).

The 2007 Final Report, “Summary of the Results from the Final Audits of the SOP-TRD Implementation Program for the Canadian Wood Preservation Industry,” (11) has shown that the wood preservation industry has largely adopted a responsible approach by following the TRD for all preservatives. In the spirit of environmental responsibility and sustainable development, the members of Wood Preservation Canada (WPC) and certain non-members have endorsed a set of principles to govern their attitude and action in environmental matters, including a commitment to “assess, plan, construct and operate facilities in compliance with all applicable regulations,” including the TRD. They have developed a self-regulation program under which facilities are certified by the Canadian Wood Preservation Certification Authority (CWPCA) (12).

In 2011, the Pest Management Regulatory Agency (PMRA) modified the labels for creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate to require, that operational procedures at wood preservation facilities be consistent with the TRD.

Environment Canada has taken this opportunity to update the 2004 TRD to incorporate some of the recommendations from the 2007 SOP-TRD Final Report and to ensure it reflects current best management practices. The 2013 revision is a modernised document meant to provide clarity, uniformity between similar pesticides and detailed recommendations to ensure better comprehension and consistency.

N.B. This document contains links to non-Environment Canada sites. Please note that Environment Canada has no control over the quality of the content on these sites. The links are provided simply as a service. Environment Canada is not responsible for incorrect or misleading data.


  1. Konasewich, D.E., and F.A. Henning. 1988. Creosote Wood Preservation Facilities: Recommendations for Design and Operation. Report EPS 2/WP/1. Ottawa (ON): Environment Canada.
  2. Konasewich, D.E., and F.A. Henning. 1988. Pentachlorophenol Wood Preservation Facilities: Recommendations for Design and Operation. Report EPS 2/WP/2. Ottawa (ON): Environment Canada.
  3. Konasewich, D.E., and F.A. Henning. 1988. Chromated Copper Arsenate (CCA) Wood Preservation Facilities: Recommendations for Design and Operation. Report EPS 2/WP/3. Ottawa (ON): Environment Canada.
  4. Konasewich, D.E., and F.A. Henning. 1988. Ammoniacal Copper Arsenate (ACA) Wood Preservation Facilities: Recommendations for Design and Operation. Report EPS 2/WP/4. Ottawa (ON): Environment Canada.
  5. Konasewich, D.E., and F.A. Henning. 1988. Pentachlorophenol (PCP) Thermal Wood Preservation Facilities: Recommendations for Design and Operation. Report EPS 2/WP/5. Ottawa (ON): Environment Canada.
  6. Das, G., and V.N.P. Mathur. 1994. Generic Code of Good Practices for Wood Preservation Facilities. International Research Group on Wood Preservation document presented at annual conference in Indonesia.
  7. United Nations Environment Programme. 1994. Environmental Aspects of Industrial Wood Preservation: A Technical Guide. UN Technical Report Series No. 20.
  8. Western Wood Preservers Institute (WWPI), Revision November 1, 2011. Best Management Practices for the Use of Treated Wood in Aquatic and Other Sensitive Environments (BMP).
  9. Environment Canada. 1999. Recommendations for the Design and Operation of Wood Preservation Facilities. Prepared for the National Office of Pollution Prevention, Environment Canada, and the Canadian Institute of Treated Wood by G.E. Brudermann, Frido Consulting. Available from Environment Canada, Ottawa. Binder.
  10. Environment Canada. 2004. Recommendations for the Design and Operation of Wood Preservation Facilities, 2004: Technical Recommendations Document. Prepared for the National Office of Pollution Prevention, Environment Canada, and the Canadian Institute of Treated Wood by G.E. Brudermann, Frido Consulting. Report EPS 2/WP/6. Available from Environment Canada, Ottawa. Binder and CD. 326 pages.
  11. Final Report, Summary of the Results from the Final Audits of the SOP-TRDImplementation Program for the Canadian Wood Preservation Industry, Prepared for Environment Canada, TRD Assessment/Implementation Working Group Manufacturers/Treaters, Steering Committee, Wood Preservation Strategic Options Process and Wood Preservation Canada by FRIDO Consulting ,G.E. Brudermann, M.Sc.F and D.E. Konasewich, PhD, P.Eng., April 10, 2007.
  12. Wood Preservation Canada, 202-2141 Thurston Drive, Ottawa, Ontario, K1G 6C9.
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