20 August 2010
HC Pub: 100111
ISBN: 978-1-100-15147-2 (Print version)
ISBN: 978-1-100-15148-9 (PDF version)
Catalogue number: H113-27/2010-3E (Print version)     
Catalogue number: H113-27/2010-3E-PDF (PDF version)

Table of Contents

• Proposed Re-evaluation Decision for Creosote, Pentachlorophenol, Chromated Copper Arsenate and Ammoniacal Copper Zinc Arsenate
• What Does Health Canada Consider When Making a Re-evaluation Decision?
• What are Creosote, Pentachlorophenol, Chromated Copper Arsenate and Ammoniacal Copper Zinc Arsenate
• Science Evaluation Summary
• Overview of Existing Risk Management Actions
• Measures to Minimize Risk
• What Additional Scientific Information is Being Requested?
• Next Steps
• Other Information

Overview

Proposed Re-evaluation Decision for Creosote, Pentachlorophenol, Chromated Copper Arsenate and Ammoniacal Copper Zinc Arsenate

An evaluation of available scientific information was conducted jointly by Health Canada's Pest Management Regulatory Agency (PMRA) and the  United States Environmental Protection Agency. After a thorough re-evaluation of the heavy duty wood preservatives creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate, Health Canada's Pest Management Regulatory Agency, under the authority of the  Pest Control Products Act, is proposing continued registration for the sale and use of creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate products in Canada.

During the course of this re-evaluation, the Canadian wood treatment industry has been actively developing and implementing a program of best management practices. These practices are contained in Recommendations for the design and operation of wood preservation facilities - technical recommendations document (Environment Canada, 2004) and are designed to minimize environmental and human health effects potentially associated with wood treatment. Since no similar, industry-wide program is in place within the United States, the United States Environmental Protection Agency has imposed specific mitigation measures relating to the operation of wood treatment facilities within the United States. Certain of these measures duplicate what has already been implemented by industry in Canada. For that reason, the approaches to risk mitigation and risk management proposed in this document differ from those required by the United States Environmental Protection Agency.

Risks identified in this re-evaluation were based on the best available information. However, this information generally predated the widespread adoption of best management practices within the Canadian industry. Therefore the re-evaluation assessment is expected to overestimate actual risks to Canadian workers.

As a result of this evaluation the PMRA found that, under the proposed conditions of use, creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate products are acceptable for continued registration. At this time, these products are critical to the wood preservation industry because there are considerable limitations with respect to registered alternatives.

Occupational risks of concern were identified for certain occupational exposures during this evaluation. Therefore as a condition of the continued registration of these products, new risk-reduction measures must be included on the labels of certain products. In additional, the PMRA is proposing the development of a risk management plan, in conjunction with Canadian stakeholders, to further address risks of concern associated with occupational exposure.

The PMRA's pesticide re-evaluation program considers potential risks as well as the value of pesticide products to ensure they meet modern standards established to protect human health and the environment. Re-evaluation draws on data from registrants, published scientific reports, information from other regulatory agencies and any other relevant information available.

This proposal affects all end-use products containing creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate registered in Canada. Once the final re-evaluation decision is made, registrants will be instructed on how to address any new requirements.

This Proposed Re-evaluation (PRVD) summarizes the science evaluation for creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate and presents the reasons for the proposed re-evaluation decision. It also proposes additional risk-reduction measures to further protect human health and the environment. Though the PRVD is a consultation document, consultation has already taken place on the science evaluation and risk assessment component of these re-evaluations. These consultations were announced, and occurred after the publication of the preliminary and revised risk assessments for the heavy duty wood preservatives. These publications were as follows:

• Re-evaluation Note REV2003-09, Update on the Re-evaluation of Heavy Duty Wood Preservative Creosote;
• Re-evaluation Note REV2004-01, Update on the Re-evaluation of CCA Heavy Duty Wood Preservative;
• Re-evaluation Note REV2004-04,Update on the Re-evaluation of Pentachlorophenol Heavy Duty Wood Preservatives;
• Re-evaluation Note REV2005-03,Update on the Re-evaluation of the Heavy Duty Wood Preservative Pentachlorophenol;
• Re-evaluation Note REV2008-08, Update on the Re-evaluation of the Heavy Duty Wood Preservatives Creosote, Pentachlorophenol and CCA.

No modifications to the underlying risk assessments were made as a result of the most recent consultation period on the revised risk assessments. Therefore, current consultations are primarily focussed on the proposed decision component of the re-evaluation, which outlines additional risk reduction and risk management measures to further protect human health and the environment.

The information is presented in two parts: i) the Overview describes the regulatory process and key points of the evaluation (i.e. the Science Evaluation summary); ii) while the full Science Evaluation provides detailed technical information on the human health, environmental and value assessments of creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate.

The PMRA will accept written comments on this proposal up to 60 days from the date of publication of this document. Please forward all comments to PMRA Publications (please see contact information on the cover page of this document).

What Does Health Canada Consider When Making a Re-evaluation Decision?

The key objective of the Pest Control Products Act is to prevent unacceptable risks to people and the environment from the use of pest control products. Health or environmental risk is considered acceptable if there is reasonable certainty that no harm to human health, future generations or the environment will result from use or exposure to the product under its conditions or proposed conditions of registration. The Act also requires that products have value when used according to the label directions. Conditions of registration may include special precautionary measures on the product label to further reduce risk.

To reach its decisions, the PMRA applies hazard and risk assessment methods as well as policies that are rigorous and modern. These methods consider the unique characteristics of sensitive subpopulations in both humans (such as children) and organisms in the environment (for example, those most sensitive to environmental contaminants). These methods and policies also consider the nature of the effects observed and the uncertainties present when predicting the impact of pesticides. For more information on how the PMRA regulates pesticides, the assessment process and risk-reduction programs, please visit the Pesticides and Pest Management portion of Health Canada's website.

Before making a re-evaluation decision on creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate, the PMRA will consider all comments received from the public in response to this consultation document.

The PMRA will then publish a Re-evaluation Decision on creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate, which will include the decision, the reasons for it, a summary of comments received on the proposed registration decision and the PMRA's response to these comments.

For more details on the information presented in this Overview, please refer to the Science Evaluation of this consultation document.

What are Creosote, Pentachlorophenol, Chromated Copper Arsenate and Ammoniacal Copper Zinc Arsenate

Creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate, are heavy duty wood preservatives applied through high pressure impregnation in a treatment cylinder, or retort, at treatment facilities. This process imparts chemicals into wood to a depth that provides long-term control of fungi, insects and marine borers.

Creosote is a distillate of coal tar and consists of liquid and solid polycyclic aromatic hydrocarbons, other heterocyclic aromatic substances and some tar acids and bases. It is used primarily in the treatment of railroad ties, utility poles, marine pilings and industrial construction timbers. In Canada, a non-pressure treatment brush-on creosote formulation is also registered as a commercial class product for application to cut ends and drill holes of pressure-treated wood product.

Pentachlorophenol is produced by reacting chlorine with phenol at high temperatures in the presence of a catalyst. Contaminants including hexachlorobenzene, dioxins and furans are produced in the production process. These contaminants, however, are regulated to the lowest achievable levels, as per the Government of Canada's Toxic Substances Management Policy. Pentachlorophenol is used primarily to treat electrical utility poles and crossarms. It is also used on posts and industrial construction timbers. In addition to pressure treatment application, pentachlorophenol is also applied by thermal treatment.

Chromated copper arsenate is a mixture of copper oxide, and chromic and arsenic acids. Chromated copper arsenate was widely used in residential applications (for example, play-structures, decks, picnic tables, residential fencing, etc.) prior to the voluntary withdrawal of such uses by registrants in 2004. These changes were detailed in Re-evaluation Note REV 2002-03, Chromated Copper Arsenate (CCA), and Re-evaluation Note REV 2006-07, Label Guidance for Use of Chromated Copper Arsenate (CCA). Chromated copper arsenate is currently used for industrial wood applications such as utility poles, construction timbers and marine structures.

Ammoniacal copper zinc arsenate is prepared by mixing and oxidizing arsenic acid, copper oxide, zinc oxide, ammonium hydroxide, ammonium bicarbonate and water. Ammoniacal copper zinc arsenate is used for industrial applications such as construction timbers, marine structures and utility poles. Although presently registered (under the Pest Control Products Act), ammoniacal copper zinc arsenate was not being used in Canada at the time of publication of this document.

Science Evaluation Summary

Creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate were jointly re-evaluated by Health Canada's Pest Management Regulatory Agency and the United States Environmental Protection Agency. For this reason, readers are referred to the United States Environmental Protection Agency Reregistration Eligibility Decision documents and related material for a detailed summary of the science evaluations. These documents can be found on the USEPA website on the  Pesticide Reregistration Status page.

Elements of the science evaluation that are specific to Canadian regulations, or Canadian product registrations, are presented in the Science Evaluation section of this document.

Overview of Existing Risk Management Actions

Recommendations for the Design and Operation of Wood Preservation Facilities: Technical Recommendations Document (Environment Canada, 2004)

The wood preservation industry, in conjunction with Environment Canada, has developed and implemented best management practices within the vast majority of wood treatment facilities. These standards were developed in consultation with other stakeholders, including the PMRA. These practices are contained in Recommendations for the design and operation of wood preservation facilities - technical recommendations document (Environment Canada, 2004).

These voluntary standards establish benchmarks for design and operation of wood preservation facilities, to minimize environmental and human health effects potentially associated with heavy duty wood preservation facilities. These objectives are consistent with PMRA's mission to protect human health and the environment by minimizing the risks associated with pest control products.

At the time of publication, 93% of wood treatment facilities were certified as being in conformance with the technical recommendations. Though these best management practices are voluntary industry standards, Environment Canada continues to regulate this sector under the Canadian Environmental Protection Act and has taken regulatory action against specific facilities where required.

Disposal of out-of-use treated wood and treated wood waste

Environment Canada, in consultation with the wood preservation sector, published a guidance document entitled Industrial Treated Wood Users Guidance Document, in 2004. This document lists recommendations designed to promote environmentally responsible management of the purchase, use, storage and disposal of wood treated with heavy duty wood preservatives.

Various other aspects of wood treatment facilities are also regulated by the PMRA, provincial ministries of the environment, transport, occupational health and safety authorities as well as municipal governments.

International Activities: UN Convention on Long-range Transboundary Air Pollution (LRTAP)

In 2008, pentachlorophenol was nominated as a Persistence Organic Pollutant (POP) under LRTAP by the European Community. If designated a POP, pentachlorophenol could be subject to elimination of production and use by Parties to the Convention, which include Canada. In December 2009, the Convention's Executive Body concluded that pentachlorophenol itself does not meet all the POPs criteria; however, the listing of pentachlorophenol as a POP is still under consideration since its transformation product, pentachloroanisol, is found in the Arctic and has persistent, bioaccumulative and toxic properties. Currently, pentachloroanisol is under review by LRTAP. It is not known to what extent the presence of pentachloroanisol in remote areas is a result of the degradation of organochlorines already present in those areas, versus a result of the long range transport of pentachlorophenol. The Government of Canada (Health Canada Pest Management Regulatory Agency and Environment Canada) is actively participating in this international process, at both the scientific and negotiating levels, and will keep the Canadian public informed regarding future LRTAP decisions.

Measures to Minimize Risk

Registered pesticide product labels include specific instructions for use. Directions include risk-reduction measures to protect human and environmental health. These directions must be followed by law.

Risk-reduction measures are being proposed to address potential risks identified in this assessment. These measures, in addition to those already identified on HDWP product labels, are designed to further protect human health and the environment. The following additional key risk-reduction measures are being proposed.

Additional Key Risk-Reduction Measures

Human Health

Requiring protective equipment, engineering controls and protective practices as per Recommendations for the design and operation of wood preservation facilities - technical recommendations document (Environment Canada) to protect treatment plant workers.

Environment

Update "environmental hazards" and "directions for use" sections of product labels to address potential contamination via runoff and improper disposal.

Risk Management Plan

To further address risks of concern associated with occupational exposure, the PMRA is proposing the development and implementation of a heavy duty wood preservative risk management plan. This would occur in consultation with stakeholders, and the plan would be periodically evaluated for effectiveness after implementation. In conjunction with this PRVD, a separate document, Re-evaluation Note REV2010-05, Call for Risk Management Proposals for Heavy Duty Wood Preservatives Creosote, Pentachlorophenol Chromated Copper Arsenate and Ammoniacal Copper Zinc Arsenate) is being published to solicit stakeholder input on risk management options.

What Additional Scientific Information is Being Requested?

Additional data requirements for creosote, pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate are described in the United States Environmental Protection Agency Reregistration Eligibility Decision documents. This additional confirmatory scientific information is being requested from Canadian registrants as per the United States Environmental Protection Agency Reregistration Eligibility Decision documents.

Additional Canadian specific data requirements relating to chemistry are described in the Science Evaluation.

Next Steps

Before making a re-evaluation decision on creosote pentachlorophenol, chromated copper arsenate and ammoniacal copper zinc arsenate, the PMRA will consider all comments received from the public in response to the proposed decision portion of this consultation document. The PMRA will then publish a Re-evaluation Decision, which will include the decision, the reasons for it, a summary of comments received on the proposed decision and the PMRA's response to these comments.

Other Information

Test data on which the decision is based will be available for public inspection, upon application, in the PMRA's Reading Room (located in Ottawa) or on the  United States federal Public Docket at the following docket numbers:

EPA-HQ-OPP-2003-0248 (Creosote)
EPA-HQ-OPP-2004-0402 (Pentachlorophenol)
EPA-HQ-OPP-2003-0250 (CCA, ACZA)