Monocyclic and Bicyclic Sesquiterpenes Group - information sheet

Part of the Terpenes and Terpenoids Group

On this page

• Overview
• About these substances
• Human and ecological exposures
• Key health and ecological effects (hazard)
• Risk assessment outcomes
  • Proposed screening assessment conclusions
• Preventive actions and reducing risk
• Related information

Overview

• The Government of Canada conducted a science-based screening assessment, under the Canadian Environmental Protection Act, 1999 (CEPA 1999), to address the potential for harm to Canadians and to the environment from 16 substances in the Monocyclic and Bicyclic Sesquiterpenes Group .
• The risk posed by a substance is determined by considering both its hazardous properties (its potential to cause adverse human health or ecological effects) and the amount of exposure there is to people and the environment.
• As a result of the draft screening assessment, the Government is proposing that 3 substances in this group (T & T clove oil, sandalwood oil, and guaiazulene) may be harmful to human health due to some exposures of concern.
• The other 13 substances are proposed to not be harmful to human health, and none of the substances are proposed harmful to the environment, at levels of exposure considered in the assessment.
• The Government published a risk management scope document for T & T clove oil, sandalwood oil, and guaiazulene to initiate discussions with stakeholders on the development of risk management options noted below.

About these substances

• There are 76 substances in the larger Terpenes and Terpenoids Group being assessed under the Chemicals Management Plan (CMP).
  • Fifteen terpene and terpenoid substances are included in the screening assessment of the Acyclic, Monocyclic, and Bicyclic Monoterpenes Group.
  • Four of the substances in the larger group were determined to be of low concern to both human health and the environment through other approaches. The conclusions for substances with the CAS RN 4572-09-2 and 25428-43-7 are provided in the Final Screening Assessment for the Rapid Screening of Substances with Limited General Population Exposure. Conclusions for the substances with CAS RNs 29350-73-0 and 68916-97-2 are provided in the Final Screening Assessment for Substances Identified as Being of Low Concern using the Ecological Risk Classification of Organic Substances and the Threshold of Toxicological Concern (TTC)-based Approach for Certain Substances.
  • The screening assessment summarized here focuses on 16 of the 76 substances. The 16 substances are referred to as the Monocyclic and Bicyclic Sesquiterpenes Group.
  • The ecological hazard and exposure potentials of these 16 substances were classified using the Ecological Risk Classification of Organic Substances (ERC) Approach.
  • Decisions on the remaining 41 terpene and terpenoid substances in the larger group will be or are provided in other screening assessments.
• The 16 substances in the assessment have been divided into 3 subgroups (based on chemical structure, properties, and/or toxicity) and 2 individual substances (sandalwood oil and guaiazulene).
  • Subgroup 1 contains bisabolene, copaiba balsam, ginger oil, alpha-bisabolene, sandalore, and santol pentenol.
  • Subgroup 2 contains beta-caryophyllene, guaiene, alpha-guaiene, valencene, and terpenes and terpenoids (T & T) clove oil.
  • Subgroup 3 contains guaiol, elemol, and bulnesol.
• These substances may be components of essential oils found in a wide variety of plants. Some of them occur naturally in food and some may also be used as food flavouring agents.
• According to information gathered by the Government, these substances are used in Canada as fragrances in:
  • self-care products, including body lotion, massage products, hair care products, oral care products, and various drugs, non-prescription and natural health products.
  • cleaning products and air fresheners.
• Most of them are also present in pest control products as formulants.

Human and ecological exposures

• Canadians may be exposed to these substances either through dermal (skin) or inhalation (breathing in) routes from the use of various self-care products (that is, cosmetics, drugs, and natural health products), cleaning products or air fresheners. Canadians may also be exposed to some of these substances through their natural presence in food or possible use as a food flavouring agent. Exposure from environmental sources are not expected.
• According to the information considered under the ERC Approach, all of these substances were identified as having low ecological exposure potential, except for copaiba balsam, which was classified as having a moderate ecological exposure potential based on its overall persistence and conservative quantity estimate.

Key health and ecological effects (hazard)

• To inform the health effects characterization in the screening assessment, international and national reports of data on some of these substances and their components were considered. This included assessments by the United States Environmental Protection Agency and the European Chemicals Agency (ECHA), among others.
• The 6 substances in subgroup 1 (ginger oil, bisabolene, alpha-bisabolene, santol pentenol, sandalore, and copaiba balsam) demonstrated low human hazard potential.
• Due to limited data for a number of substances in this assessment, a comparative approach, called read-across, was used for assessing potential health effects for some of these substances.
• For subgroup 2 (beta-caryophyllene, T & T clove oil, guaiene, alpha-guaiene and valencene), hazard information for beta-caryophyllene (the main component in T&T clove oil) was used to inform the hazard assessment. For beta-caryophyllene, critical health effects considered in the assessment were lymphoid system effects in males, and effects in the liver and mesenteric lymph nodes in both sexes.
• For subgroup 3 (guaiol, bulnelsol, elemol), critical effects on the male reproductive system were used in characterizing potential risk to human health.
• For sandalwood oil, critical health effects considered in the assessment included:
  • From dermal exposure, decrease in body weight gain, decreased ability to feed, and effects on the liver and testes.
  • From oral exposure, sedation, ataxia, and reduction of body weight gain in females, reduced intake of food, and developmental effects.
• For guaiazulene, critical health effects considered in the assessment included:
  • Through dermal exposure, effects on the testes and non-cancerous tumors in various organs.
  • Through inhalation exposure, effects on the respiratory system, especially on the nose and lungs.
• According to information considered under the ERC Approach, these substances were identified as having a low ecological hazard potential, except for the following:
  • Santol pentenol was identified as having a moderate hazard potential due to its moderate potential to cause adverse effects in aquatic food webs.
  • T & T clove oil, alpha-guaiene, and valencene were identified as having a high hazard potential, due to their high potential to cause adverse effects in aquatic food webs, given their bioaccumulation potential.

Risk assessment outcomes

• The 6 substances in subgroup 1 (ginger oil, bisabolene, alpha-bisabolene, santol pentenol, sandalore, and copaiba balsam) are considered to be low risk to human health due to their low hazard potential.
• For 3 of the 5 substances in subgroup 2 (beta-caryophyllene, guaiene, and valencene) and 2 substances in subgroup 3 (bulnelsol and elemol), using a comparison of levels to which Canadians may be exposed to these substances and levels associated with critical health effects, it was determined that the risk to human health is low.
• The risk to human health is also considered to be low for alpha-guaiene (in subgroup 2) and guaiol (in subgroup 3) since limited sources of exposure were identified.
• There may be a potential risk to human health from the use of T & T clove oil (in subgroup 2), sandalwood oil, and guaiazulene in certain products available to consumers. This was determined based upon a comparison of levels to which Canadians may be exposed to each of these substances from the following uses, and levels associated with critical effects:
  • For T & T clove oil, combined dermal and inhalation exposure from its use as an essential oil as a body fragrance (for exposure of 2 to 8-year-old children)
  • For sandalwood oil, dermal exposure from the use of body lotion, massage oil (for infants and children up to 8 years old), and use of the essential oil as a body fragrance
  • For guaiazulene, from dermal or inhalation exposures from its use in a hair perm or straightening product
  • Other exposures to these substances were also characterized and were not a concern, as detailed in the screening assessment.
• Based upon the outcome of the ERC Approach, all 16 of these substances are considered unlikely to be causing ecological harm.
• The Government of Canada published the Draft Screening Assessment for the Monocyclic and Bicyclic Sesquiterpenes Group on May 8, 2021. The public is invited to comment on the assessment during the 60-day public comment period ending on July 7, 2021.

Proposed screening assessment conclusions

• The Government is proposing that T & T clove oil, sandalwood oil, and guaiazulene may each be harmful to human health at levels of exposure considered in the assessment. It is also proposed that ginger oil, bisabolene, alpha-bisabolene, santol pentenol, sandalore, copaiba balsam, beta-caryophyllene, guaiene, alpha-guaiene, valencene, guaiol, bulnesol, and elemol are not harmful to human health at levels of exposure considered in the assessment.
• The Government is also proposing that none of the 16 substances in the Monocyclic and Bicyclic Sesquiterpenes Group are entering the environment at levels that are harmful to the environment.
• Also, it is proposed that T & T clove oil and guaiazulene meet the persistence and bioaccumulation criteria, and that sandalwood oil does not meet the persistence or bioaccumulation criteria, as set out in the Persistence and Bioaccumulation Regulations of CEPA 1999.

Preventive actions and reducing risk

• The Government of Canada published the Risk Management Scope for Certain Terpenes and Terpenoids within the Monocyclic and Bicyclic Sesquiterpenes Group on May 8, 2021. The public is invited to comment on this document during the 60-day public comment period ending on July 7, 2021.
• If the proposed conclusion is confirmed in the final screening assessment, the Government will consider adding T & T clove oil, sandalwood oil, and guaiazuleneto Schedule 1 of CEPA 1999, also called the List of Toxic Substances. Adding a substance to the list does not restrict its use, manufacture or import. Rather, it enables the Government to take risk management actions under CEPA 1999.
• The Government is also considering the following actions to address human health concerns:
  • Regulatory and/or non-regulatory measures to prevent or reduce exposures to T & T clove oil and guaiazulene from certain cosmetics
  • Measures to reduce exposures to sandalwood oil from certain cosmetics by describing sandalwood oil as a prohibited or restricted ingredient on Health Canada's Cosmetic Ingredient Hotlist. The Hotlist is used to communicate that certain substances may not be compliant 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.
• Information is being sought by the Government to inform risk management decision-making. Details can be found in the proposed risk management scope, including where to send information during the public comment period, ending July 7, 2021.
• Risk management actions 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.
• Information on the risk management of substances addressed under the CMP is available.

Related information

• These substances are found in products available to consumers. Canadians should follow any safety warnings and directions related to the product and dispose of productsresponsibly.
• Visit Do it for a Healthy Home for information on chemical safety in and around the home, including information on T & T clove oil, sandalwood oil, and guaiazulene (for consumers).
• Some terpene and terpenoid substances or their components (for example, beta-caryophyllene and valencene) have been identified in vaping products. Vaping products (also known as electronic cigarettes) may represent an additional source of exposure to these substances. The assessment of risk to Canadians from this use, including risk relative to that associated with conventional cigarettes, and possible options to mitigate risk associated with these products, are being addressed through a separate legislative framework. These exposures are not characterized further in the screening assessment summarized on this page.
• The screening assessment focused on potential risks from exposure of the general population of Canada, rather than occupational exposure. Hazards related to chemicals used in the workplace are defined within the Workplace Hazardous Materials Information System (WHMIS). For information concerning workplace health and safety and what steps to take in the workplace, Canadians should consult their employer and/or the Occupational Health and Safety Regulator in their jurisdiction.