Evaluation Report ERC2014-01, Tea Tree Oil

Pest Management Regulatory Agency
4 March 2014
ISSN: 1911-8082 (PDF version)
Catalogue number: H113-26/2014-1E-PDF (PDF version)

This page is a summary of the Evaluation Report. If you would like more detail, please request the full Evaluation Report.

To obtain an electronic copy of the document, Evaluation Report ERC2014-01, Tea Tree Oil, please contact our publications office.

Should you require further information please contact the Pest Management Information Service.

Summary

Table of Contents

Registration Decision for Compound Tea Tree Oil

Health Canada's Pest Management Regulatory Agency (PMRA), under the authority of the  Pest Control Products Act and  Regulations, has granted conditional registration for the sale and use of Tea Tree Oil Technical and Timorex Gold, containing the technical grade active ingredient tea tree oil, to control powdery mildew on greenhouse pepper, tomato and cucumber, suppress powdery mildew on grape, strawberry and cucurbit vegetables, suppress downy mildew on grape and greenhouse cucumber, and suppress late blight on greenhouse tomato.

An evaluation of available scientific information found that, under the approved conditions of use, the product has value and does not present an unacceptable risk to human health or the environment.

Although the risks and value have been found acceptable when all risk reduction measures are followed, the applicant must submit additional scientific information as a condition of registration.

This Summary describes the key points of the evaluation, while the Science Evaluation section of Evaluation Report ERC2014-01, Tea Tree Oil provides detailed technical information on the human health, environmental and value assessments of Tea Tree Oil Technical and Timorex Gold.

What Does Health Canada Consider When Making a Registration 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 acceptableFootnote 1 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 proposed conditions of registration. The Act also requires that products have valueFootnote 2 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 modern, rigorous risk-assessment methods and policies. These methods consider the unique characteristics of sensitive subpopulations in humans (for example, children) as well as 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 when predicting the impact of pesticides. For more information on how the PMRA regulates pesticides, the assessment process and risk-reduction programs, please refer to the following:

What Is Tea Tree Oil?

Tea tree oil is extracted from a cultivated tea tree native to Australia, New Zealand and Southeast Asia. Tea tree oil contains over 100 components, mostly monoterpenes, sesquiterpenes and their alcohols. As the active ingredient in Timorex Gold, tea tree oil may disrupt cell membrane of the targeted fungal pathogens, though the exact biochemical mode of action is still not fully understood.

Health Considerations

Can Approved Uses of Tea Tree Oil Affect Human Health?

Tea tree oil is unlikely to affect human health when used according to label directions.

Potential exposure to tea tree oil may occur through the diet (food and water) or when handling and applying the end-use product, Timorex Gold, which is proposed as a commercial fungicide for application to various vegetable and fruit crops. When assessing health risks, two key factors are considered: the levels where no health effects occur and the levels to which people may be exposed. The dose levels used to assess risks are established to protect the most sensitive human population (for example, children and nursing mothers). Only uses for which the exposure is well below levels that cause no effects in animal testing are considered acceptable for registration.

Tea tree oil is slightly acutely toxic via the oral route and of low acute toxicity via the dermal and inhalation routes of exposure. It is a severe eye and skin irritant, and is considered to be a skin sensitizer. Although tea tree oil has low acute inhalation toxicity, because of its eye and skin irritancy, it is considered to be a potential respiratory irritant if inhaled. Consequently, the hazard signal words, "CAUTION POISON", "DANGER - EYE AND SKIN IRRITANT", and "POTENTIAL SKIN SENSITIZER" are required on the label.

The acute toxicity of Timorex Gold was low via the oral, dermal, and inhalation routes of exposure. It was moderately irritating to the eyes and skin, and is considered to be a skin sensitizer. Because of its eye and skin irritancy, it is considered to be a potential respiratory irritant if inhaled. As a result, the hazard signal words, "WARNING-EYE AND SKIN IRRITANT" and "POTENTIAL SKIN SENSITIZER" are required on the label.

Residues in Water and Food

Dietary risks from food and water are not of concern.

Timorex Gold is to be applied as a foliar spray using conventional equipment to prevent fungal growth on vegetables and fruit in greenhouses, nurseries, and fields. The major components of tea tree oil (i.e., monoterpenes, sesquiterpenes, and related alcohols) are volatile, and after application, tea tree oil is expected to substantially volatilize with low residence times on plants and soil. In residue trials conducted in Europe, the levels of tea tree oil components on treated crops were less than the limit of quantification 48 hours after the application of Timorex Gold. A preharvest interval of four days is required on the label to further encourage the dissipation of any residues of tea tree oil prior to harvesting treated crops. Also, consumers are exposed to low levels of tea tree oil components in the diet through their use as flavouring substances, in sanitizing solutions for food-processing equipment, and in coatings on food contact surfaces.

Many of the components of tea tree oil have low water solubility, and because of the expected volatilization and low residence time for tea tree oil in environmental media, there is not likely to be any significant contamination of ground or surface water sources of drinking water. In addition, the label directions for Timorex Gold indicate that the product should not be applied directly to water, and that water should not be contaminated when cleaning equipment or disposing of wash water.

Therefore, it is expected that the use of Timorex Gold will not appreciably increase dietary exposure to the components of tea tree oil above existing low background intakes provided that the preharvest interval is observed. Also, it is expected that potential intakes of tea tree oil from drinking water will be negligible. Therefore, the use of Timorex Gold according to label directions is not expected to result in unacceptable dietary or drinking water risks.

Occupational and Bystander Risks from Handling Timorex Gold

Occupational and bystander risks are not of concern when Timorex Gold is used according to label directions, which include protective measures.

There is a potential for dermal and inhalation occupational exposure to tea tree oil during the mixing, loading, and application of Timorex Gold. It is expected that such exposures can be mitigated if workers observe a four hour restricted entry interval (REI) and the precautionary and hygiene statements on the label (for example, wearing of personal protective equipment). In addition, for greenhouse applications, the greenhouse vents should be open and the ventilation fans operating during the REI.

Since Timorex Gold is applied by commercial applicators, potential bystander exposure can be mitigated by following precautionary statements on the label restricting access to the sites of application during mixing, loading, application, and the REI. The product should also not be applied when bystanders are in the vicinity of fields or in areas of greenhouses containing crops to be treated, or present in adjacent structures or buildings where they could be exposed via post-application ventilation from treated greenhouses.

Therefore, occupational exposures to individuals handling Timorex Gold are not expected to result in any unacceptable risks and bystander exposures to the product are expected to be negligible when the product is used according to label directions.

Environmental Considerations

What Happens When Tea Tree Oil Is Introduced Into the Environment?

Tea Tree Oil Technical and its associated end-use product, Timorex Gold, will enter the environment when applied as a fungicide, using field and airblast sprayers, on various field and greenhouse crops. Tea tree oil is composed of several constituents that are all considered to be highly volatile; substantial volatilization is expected within the first 24 hours of application from plant, soil, and water surfaces. Tea tree oil constituents are quickly broken down in air through atmospheric reactions. Because of the short residence time in the environment, exposure to groundwater through leaching and surface waters through runoff is not expected to be significant. A rapid rate of volatilization followed by breakdown in air means that exposure to non-target organisms is expected to be limited. However, acute exposure from direct contact with the spray or spray drift may be possible and was assessed. Based on this, the potential for acute risk to fish, invertebrates, amphibians, and beneficial arthropods was identified. Hazard label statements and mitigative measures are required on the label.

Value Considerations

What Is the Value of Timorex Gold?

Timorex Gold, containing tea tree oil, has demonstrated effectiveness in controlling powdery mildew on greenhouse pepper, tomato and cucumber, suppressing powdery mildew on grape, strawberry and cucurbit vegetables, suppressing downy mildew on grape and greenhouse cucumber, and suppressing late blight on greenhouse tomato. Timorex Gold may be applied before disease development or at the first sign of disease. The multicomponent nature of tea tree oil may greatly reduce the potential for resistance development. Timorex Gold provides a non-conventional option for Canadian growers, especially for organic production.

Measures to Minimize Risk

Labels of registered pesticide products include specific instructions for use. Directions include risk-reduction measures to protect human and environmental health. These directions must be followed by law.

The key risk-reduction measures being proposed on the label of Timorex Gold to address the potential risks identified in this assessment are as follows.

Key Risk-Reduction Measures

Human Health

The signal words, "CAUTION POISON", "DANGER - EYE AND SKIN IRRITANT", "POTENTIAL SKIN SENSITIZER", and "PREVENT ACCESS BY UNAUTHORIZED PERSONNEL" are required on the principal display panel for the technical grade active ingredient label.

The statements, "PREVENT ACCESS BY UNAUTHORIZED PERSONNEL", "Harmful if swallowed. Severely irritating to the eyes, skin and respiratory tract. DO NOT get in eyes, on skin or clothing, or inhale sprays, mists or vapours." are required for the PRECAUTIONS section of the secondary display panel of the technical grade active ingredient.

The signal words, "WARNING-EYE AND SKIN IRRITANT" and "POTENTIAL SKIN SENSITIZER" are required on the principal display panel for the end-use product label.

The following statements are required for the PRECAUTIONS section of the secondary display panel of the end-use product:

  • "KEEP OUT OF REACH OF CHILDREN", "Causes eye, skin, and mucous membrane irritation. DO NOT get in eyes, on skin or clothing, or inhale, sprays, mists or vapours. Potential skin sensitizer."

  • "Product contains a petroleum distillate solvent"

  • "Workers potentially exposed to the product through mixing, loading, application, clean-up and repair activities must wear chemical-resistant goggles or a face shield, a NIOSH/MSHA-approved respirator (R95), long-sleeved shirt and long pants, chemical-resistant gloves and shoes plus socks."

  • "Keep bystanders out of the areas of the greenhouse to be treated for the duration of the treatment and the restricted entry interval (REI)."

  • "Do not apply to field crops when bystanders are in the vicinity of the fields to be treated."

  • "Apply only when the potential for drift to areas of human habitation or areas of human activity such as houses, cottages, schools, and recreational areas is minimal. Take into consideration wind speed, wind direction, temperature inversion, application equipment, and sprayer settings."

The following statements are required for the APPLICATION DIRECTIONS section of the secondary display panel of the end-use product:

  • "A restricted re-entry interval (REI) of four hours must be observed following application. Do not enter or allow worker entry into treated areas during the REI. For greenhouse applications, vents should be opened and ventilation fans should be operational during the REI."

  • "Treated crops should not be harvested until a preharvest interval of four days has passed."

Environment

Label statements indicating toxicity to aquatic organisms and beneficial arthropods are required. Buffer zone label statements for the protection of aquatic environments are also required.

What Additional Scientific Information Is Being Requested?

Although the risks and value have been found acceptable when all risk-reduction measures are followed, the applicant must submit additional scientific information as a condition of registration. More details are presented in the Science Evaluation Section of Evaluation Report ERC2014-01, Tea Tree Oil or in the Section 12 Notice associated with these conditional registrations. The applicant must submit the following information within the time frames indicated.

Human Health

  • All published and unpublished studies of the developmental toxicity of tea tree oil must be submitted by 1 September 2015.
  • Information to characterize the metabolic pathways of the major components of tea tree oil and whether residues of the major components and their metabolites are present on treated crops after the application of Timorex Gold must be submitted by 1 September 2015.

Other Information

As these conditional registrations relate to a decision on which the public must be consultedFootnote 3, the PMRA will publish a consultation document when there is a proposed decision on applications to convert the conditional registrations to full registrations or on applications to renew the conditional registrations, whichever occurs first.

The test data cited in Evaluation Report ERC2014-01, Tea Tree Oil (i.e. the test data relevant in supporting the registration decision) will be made available for public inspection when the decision is made to convert the conditional registrations to full registrations or to renew the conditional registrations (following public consultation). If more information is required, please contact the PMRA's Pest Management Information Service by phone (1-800-267-6315) or by e-mail (pmra.infoserv@hc-sc.gc.ca).

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