Tricyclic Sesquiterpenes and Triterpenoids Group - information sheet

Part of the Terpenes and Terpenoids Group

Publications summarized

• Draft Assessment for Tricyclic Sesquiterpenes and Triterpenoids Group (Terpenes and Terpenoids) (published on March 1, 2025 for a 60-day public comment period ending on April 30, 2025).
• Risk Management Scope for Tricyclic Sesquiterpenes and Triterpenoids Group: Cedarwood oil, Texan cedarwood oil, Enoxolone, Mimosa oil, and Ivy extract (published on March 1, 2025 for a 60-day public comment period ending on April 30, 2025).
• Associated notice: Canada Gazette, Part I: Vol. 159, No. 9 – March 1, 2025

On this page

• Overview
• About these substances
• Human and ecological exposures
• Key health and ecological effects (hazard)
• Consideration of subpopulations who may have greater susceptibility or greater exposure
• Risk assessment outcomes
  • Proposed assessment conclusions
• Preventive actions and risk reduction
  • Where to find updates on risk management actions
• Related resources

Overview

• The Government of Canada conducts risk assessments of substances under the Canadian Environmental Protection Act, 1999 (CEPA) to determine whether they present or may present a risk to human health or to the environment.
  • The risks posed by a substance are determined by both its hazardous properties (potential to cause adverse human health or ecological effects) and the amount or extent of exposure to people or the environment.
  • When needed, the Government applies risk management instruments under CEPA and other federal acts to help prevent or reduce potential harm.
• As a result of the assessment, the Government is proposing that cedarwood oil, Texan cedarwood oil, enoxolone, mimosa oil and ivy extract may be harmful to human health at levels of exposure considered in the assessment.
  • The exposures of concern are from a variety of cosmetics, natural health products (NHPs), non-prescription drugs (NPDs), and other products available to consumers. Use of essential oils or products containing some of these substances in do-it-yourself (DIY) applications, such as in aroma diffusers or massage oils, are also of concern. These 5 substances are associated with effects on human health.
• Risk management actions are proposed to help reduce exposures of people in Canada to these 5 substances from certain cosmetics, NHPs and NPDs, consumer products (including essential oils or products), and foods, as described further below.
• The Government is also proposing that alpha-cedrene, thujopsene, alpha-gurjunene, beta-patchoulene, beta-cedrene, T&T cedarwood oil, amboryl acetate, allantoin glycyrrhetinic acid, and American ginseng extract are not harmful to human health at levels of exposure considered in the assessment.
• The ecological hazard and exposure potentials of the 14 substances in this group were classified using the Ecological Risk Classification of Organic Substances (ERC) Approach. None of the 14 substances in this group are proposed to be causing harm to the environment.

About these substances

• There are 76 substances in the larger Terpenes and Terpenoids Group for which assessment started under the third phase of the Chemicals Management Plan (CMP). Information on these substances is provided in their corresponding assessments, which are outlined in the background section of the Tricyclic Sesquiterpenes and Triterpenoids Group web page.
• Most of these terpene and terpenoid substances are naturally occurring and are either essential oils, plant extracts or components of essential oils or extracts from a wide variety of plants. Essential oils are mixtures of volatile, organic compounds that contribute to the flavour and fragrance of the plant. The plant-derived essential oils have many components and can be extracted from different parts of the plant (for example, leaves, seeds, stems, flowers, roots, fruits, woods, barks, grass, gum, tree blossoms, bulbs, and flower buds).
• The assessment summarized here focuses on 14 substances, referred to as the Tricyclic Sesquiterpenes and Triterpenoids Group. For the human health assessment, 10 of the substances are being addressed under 2 subgroups due to similarities in chemical structure, properties or toxicity, as follows:
  • 8 substances in Tricyclic Sesquiterpene subgroup 1: alpha-cedrene, thujopsene, alpha-gurjunene, beta-patchoulene, beta-cedrene, cedarwood oil, T&T cedarwood oil, and Texan cedarwood oil
  • 2 substances in Triterpenoid subgroup 2: enoxolone and allantoin glycyrrhetinic acid.
• The other 4 substances (amboryl acetate, mimosa oil, ivy extract, and American ginseng extract) are being addressed individually.
• Further details on the substance names and CAS RNs for the group of 14 substances are found in the summary of publications section of the Tricyclic Sesquiterpenes and Triterpenoids Group web page.
• According to information gathered by the Government, the substances in this group are generally used as fragrances in cosmetics, NHPs, NPDs, cleaning products and air fresheners. Some of them are also present in pest control products as formulants. Cedarwood oil is an active ingredient used only to make pest control products intended for export out of Canada. In addition, some of them occur naturally in foods and are potentially used as food flavouring agents.
• Also, certain terpene and terpenoid substances within the group that have aromatic properties are available to consumers as essential oils or products at a concentration of up to 100%. It is possible that these are used to create DIY products, such as aromatic diffusers, massage oils, bath products, body moisturizers, and facial steamers.

Human and ecological exposures

• The assessment indicates that exposure of people in Canada to the substances in this group from the environment is not expected to impact human health.
• People in Canada may be exposed to substances in this group from certain cosmetics, NHPs, NPDs, food flavouring agents, cleaning products, and air fresheners. Exposures may also occur from the use of these substances in DIY or homemade applications, for example, when using essential oils or products to make DIY massage oils or aromatic diffusers.
• Other than limited dietary exposure of some of these substances, there were no identified sources of exposure of the general population to thujopsene, alpha-gurjunene, beta-patchoulene, beta-cedrene, amboryl acetate, and allantoin glycyrrhetinic acid.
• According to the information considered under the ERC Approach, 13 of the substances in the group were identified as having low ecological exposure potential. Mimosa oil was classified as having a moderate ecological exposure potential due to its overall persistence (ability to stay in the environment for a long time) and moderate quantities of use.

Key health and ecological effects (hazard)

• To help inform the health effects characterization in the assessment, international and national data on these substances or similar substances were considered. This included assessments by the United States Environmental Protection Agency and the European Chemicals Agency, among others.
• There were limited health effects (hazard) data for some of the substances in this group. Therefore, data on main components of the substances or a comparative approach using a similar chemical (called read-across) was used for assessing potential health effects. Critical health effects are based on human and laboratory studies.
• Hazard information for cedarwood oil was used to inform the risk assessment of substances in Tricyclic Sesquiterpene subgroup 1 (alpha-cedrene, thujopsene, alpha-gurjunene, beta-patchoulene, beta-cedrene, cedarwood oil, T&T cedarwood oil, and Texan cedarwood oil). The critical effects considered for substances in subgroup 1 include effects on the thymus and thyroid hormone changes.
• Developmental neurotoxicity was identified as the critical health effect used to characterize risk for subgroup 2 (enoxolone and allantoin glycyrrhetinic acid), mimosa oil, and ivy extract.
• Human health effects of concern were not identified for amboryl acetate and American ginseng extract.
• According to information considered under the ERC Approach:
  • 8 of the 14 substances (alpha-cedrene, beta-patchoulene, beta-cedrene, cedarwood oil, T&T cedarwood oil, Texan cedarwood oil, mimosa oil, and ivy extract) were classified as having low ecological hazard potential.
  • Thujopsene, alpha-gurjunene, enoxolone, and allantoin glycyrrhetinic acid were classified as having a high hazard potential on the basis of their high potential to cause adverse effects in aquatic food webs. Enoxolone was also classified as having a high hazard potential due to its likelihood of having a high level of ecotoxicity.
  • American ginseng extract was classified as having a high hazard potential; however, the potential effects on the environment were not further investigated due to the low exposure of this substance.
  • Amboryl acetate was classified as having a moderate hazard potential due to its moderate potential to cause adverse effects in aquatic food webs.

Consideration of subpopulations who may have greater susceptibility or greater exposure

• There are groups of individuals within the Canadian population who, due to greater susceptibility or greater exposure, may be more vulnerable to experiencing adverse health effects from exposure to substances.
• Certain subpopulations are routinely considered throughout the assessment process, such as infants, children, and people of reproductive age. For instance, age-specific exposures are routinely estimated and developmental and reproductive toxicity studies are evaluated for potential adverse health effects. For substances in this group, these subpopulations were taken into account in the risk assessment outcomes.

Risk assessment outcomes

• Assessments focus on information critical to determining whether substances are harmful to human health or the environment under CEPA. This is done by considering scientific information, including information, if available, on subpopulations who may have greater susceptibility or greater exposure, vulnerable environments and cumulative effects and by incorporating a weight of evidence approach and precaution.
• Based upon a comparison of levels to which people in Canada may be exposed to cedarwood oil, Texan cedarwood oil, enoxolone, mimosa oil and ivy extract, and levels associated with critical health effects, it was determined that these substances may pose a risk to human health. As described in the assessment, concerns vary by age group, duration of use, and how people are exposed to the substances (for example, through the skin or inhaled).
  • It was determined that cedarwood oil may pose a risk to human health from dermal exposure in massage oil, fragrance, deodorant/antiperspirant (solid), moisturizer (body and face), conditioner (leave-on), body exfoliant, aftershave (face), after hair removal product (body), antiseptic skin cleanser (spray; NHP), counterirritant (spray; NHP), and irritation relief balm (NHP). Inhalation exposure to cedarwood oil in fragrance may also pose a risk. It was also determined that dermal exposure to cedarwood oil from the following DIY uses may pose a risk to human health: aroma diffuser/air freshener, massage oil, body moisturizer, and facial steamer/mist. Inhalation exposure from the DIY uses of cedarwood oil in aromatic diffusers/air fresheners and facial steamers/mists may also pose a risk.
  • Texan cedarwood oil may pose a risk to human health from dermal exposure in massage oil, fragrance, deodorant/antiperspirant (solid), and moisturizer (body and face). Also, from dermal exposure to Texan cedarwood oil used in DIY aroma diffuser/air freshener, DIY massage oil, DIY body moisturizer, and DIY facial steamer/mist. Inhalation exposure to DIY aroma diffuser/air freshener and DIY facial steamer/mist may also pose a risk.
  • Enoxolone may pose a risk to human health from exposure in face moisturizer, body moisturizer (spray and lotion), permanent hair dye, sunscreen (cream; NHP and NPD), analgesic patch (NHP), acne therapy (cream; NHP), medicated skin care product (cream; NHP), licorice tea and black licorice candy.
  • It was determined that mimosa oil may pose a risk to human health from exposure to it in fragrance (roll-on and spray), body moisturizer, face moisturizer, massage oil, massage bar, sunless tanning product, facial makeup (liquid foundation), lipstick, and sunscreen (lotion; NHP). Also, from exposure to mimosa oil from its use in DIY aroma diffuser/air freshener, DIY massage oil, and DIY body moisturizer.
  • Ivy extract may pose a risk to human health from exposure to this substance in massage oil, body moisturizer, face moisturizer, facial makeup fixer (spray), body exfoliant, and hair conditioner (leave on). Also, from the use of ivy extract in DIY massage oil and DIY body moisturizer.
• A comparison of levels to which people in Canada may be exposed to T&T cedarwood oil from food (from its use as a food flavouring agent), and levels associated with health effects, indicated that the risk to human health from exposure to this substance is low. There were no other identified sources of exposure to T&T cedarwood oil.
• Also, a comparison of levels to which people may be exposed to alpha-cedrene and levels associated with health effects determined that the risk posed by this substance is low.
• Since no health effects of concern were identified for amboryl acetate and American ginseng extract and there were no identified sources of exposure for amboryl acetate, these 2 substances are of low concern to human health. The risk to human health is also considered to be low for thujopsene, alpha-gurjunene, beta-patchoulene, beta-cedrene, and allantoin glycyrrhetinic acid since no sources of exposure were identified.
• Based upon the outcome of the ERC Approach, the 14 substances in this group are considered unlikely to be causing ecological harm.

Proposed assessment conclusions

• The Government is proposing that cedarwood oil, Texan cedarwood oil, enoxolone, mimosa oil and ivy extract may be harmful to human health at levels of exposure considered in the assessment. The Government is also proposing that alpha-cedrene, thujopsene, alpha-gurjunene, beta-patchoulene, beta-cedrene, T&T cedarwood oil, amboryl acetate, allantoin glycyrrhetinic acid, and American ginseng extract are not harmful to human health at levels of exposure considered in the assessment.
• The Government is also proposing that none of the 14 substances in this group are entering the environment at levels that are harmful.

Preventive actions and risk reduction

• If the proposed conclusion is confirmed in the final assessment, the Government will consider proposing to add cedarwood oil, Texan cedarwood oil, enoxolone, mimosa oil, and ivy extract to Part 2 of Schedule 1. Adding a substance to Schedule 1 does not, in itself, restrict its use, manufacture or import. Rather, it enables the Government to take enforceable risk management actions under CEPA.
  • Toxic substances that pose the highest risk (that is, meet certain criteria) are added to Part 1 of Schedule 1. These are prioritized for total, partial or conditional prohibition.
  • Other toxic substances are added to Part 2 of Schedule 1 and are prioritized for pollution prevention actions, which may include prohibition.
• Regulations specifying criteria for the classification of substances that pose the highest risk or that are carcinogenic, mutagenic or toxic to reproduction will be developed. When criteria are available, some substances considered for addition to Part 2 of Schedule 1 may instead be considered for addition to Part 1 of Schedule 1.
• Publication of the risk management scope aims to inform interested parties of proposed risk management options and initiate discussions about their development. The Government is considering the following actions to address human health concerns:

Consumer products, including essential oils or products sold directly to consumers in vials for use in DIY applications:

• Regulatory or non-regulatory actions to help reduce inhalation and/or dermal exposures to cedarwood oil, Texan cedarwood oil, mimosa oil, and ivy extract from certain consumer products.
• A public communications approach for DIY consumer product essential oils of concern for human health is also being considered.

Food:

• Regulatory or non-regulatory actions to help reduce oral exposure to enoxolone from licorice teas and black licorice candy.

Cosmetics:

• Listing cedarwood oil, Texan cedarwood oil, enoxolone, mimosa oil, and ivy extract as prohibited or restricted ingredients on Health Canada's Cosmetic Ingredient Hotlist to help reduce inhalation, dermal and/or oral exposures to these substances from certain cosmetics. The Hotlist is used to communicate that certain substances may not comply with requirements of the Food and Drugs Act or the Cosmetic Regulations. Under Canadian legislation, cosmetics that contain substances that are harmful to the user cannot be sold.

NHPs and NPDs:

• Listing cedarwood oil, enoxolone, and mimosa oil as restricted ingredients in Health Canada's Natural Health Products Ingredients Database to help reduce dermal exposure to these substances from certain topical NHPs or NPDs. Actions may aim to lower the concentration of these substances when used as non-medicinal ingredients in certain topical NHPs or NPDs to levels that are protective of human health.
• Additional information is being sought by the Government to inform risk management decision-making. Details can be found in the risk management scope, including where to send information during the public comment period, ending April 30, 2025.
• Risk management options may evolve through consideration of assessments and risk management actions published for other substances. This is to ensure effective, coordinated, and consistent risk management decision-making.

Where to find updates on risk management actions

• Additional information on the risk management of substances as well as a table of risk management actions for substances addressed under the CMP is available.
• Use the Substances Search tool to find substances that are referenced in certain legislative or regulatory instruments or on Government of Canada websites.

Related resources

• Some of the substances in this group are found in products available to consumers. People in Canada should follow any safety warnings and directions related to the product and dispose of products responsibly.
• Visit Healthy home for information on chemical safety in and around the home, including on enoxolone and essential oils and botanical extracts (for consumers).
• Cosmetics must include a list of all ingredients on the product label using the International Nomenclature of Cosmetic Ingredients (INCI) system or by chemical name when there is no INCI name. Cedrus atlantica bark oil, Cedrus atlantica wood oil, Juniperus virginiana oil, Juniperus mexicana oil, Glycyrrhetinic acid, Hedera helix (ivy) leaf/stem extract, and Hedera helix (ivy) stem extract are all INCI names. Botanicals must be listed by specifying at least the genus and species portions of the INCI name (for example, Cedrus atlantica bark oil or Cedrus atlantica wood oil may be listed as "Cedrus atlantica").
• Alpha-cedrene and alpha-gurjunene have been identified as possible ingredients in vaping products (such as electronic cigarettes and vaping devices containing cannabis), which may represent an additional source of exposure to these substances. Vaping products that do not contain cannabis are being addressed through the Tobacco and Vaping Products Act. Cannabis products that may include these substances (such as vaping products or topicals) are being addressed through the cannabis legislative framework.
• Assessments conducted under CEPA focus on risks of exposure of the general population, including populations who may be disproportionately impacted. Hazards related to chemicals used in the workplace are defined within the Workplace Hazardous Materials Information System (WHMIS). The Government of Canada recognizes that it is the responsibility of the federal, provincial and territorial occupational health and safety organizations to coordinate legislation for the safe use of chemicals in the workplace. We are working to support this role by integrating the information, tools, and technical expertise of the CMP and Health Canada's Workplace Hazardous Products Program.