2.1 Interim decision in relation to carbon monoxide

2. Interim decisions on proposed amendments referred to the Advisory Committee on Chemicals Scheduling (ACCS #26, November 2019)

2.1. Interim decision in relation to carbon monoxide

Interim decision

Pursuant to regulation 42ZCZN of the Regulations, a Delegate of the Secretary has, in relation to the proposed amendment, made an interim decision not to amend the current Poisons Standard in relation to carbon monoxide.

Reasons for the interim decision (including findings on material questions of fact)

In this section: Applicant's scheduling proposal and reasons for the proposal | Current scheduling status | Scheduling history | Australian regulations | International regulations | Current use in Australia | Summary of pre-meeting public submissions | Summary of ACCS advice/recommendations to the Delegate | Delegate's considerations | Reasons for interim decision

Applicant's scheduling proposal and reasons for the proposal

An application to create new Schedule 7, Schedule 6 and Appendix F entries for carbon monoxide was considered.

The Applicant's proposed amendments to the Poisons Standard were:

The Applicant's main points provided in support of the proposed amendment were as follows:

• Carbon monoxide gas has known potential for misuse.^[137] Inhalation of carbon monoxide gas has a high potential for causing harm (including death) without warning as it is colourless and odourless.^[138]
• Carbon monoxide has a high affinity for haemoglobin (a protein found in red blood cells responsible for transporting oxygen) to form a stable complex of carboxyhaemoglobin (COHb).^[139] As carbon monoxide binds to haemoglobin at the same sites as oxygen, but approximately 210 times more tightly, this reduces the ability for red blood cells to carry and deliver oxygen to the body.^[140] This lack of oxygen can result in tissue hypoxia and, in serious cases of carbon monoxide poisoning, can lead to organ failure and death.^[141]
• A Schedule 6 entry for carbon monoxide has been proposed on the grounds that carbon monoxide meets the toxicity scheduling factors as outlined in the Scheduling Policy Framework^[142] as follows:
  • The substance has a moderate to high toxicity, which may cause death or severe injury (including destruction of living tissue) if inhaled, taken internally, or in contact with skin or eyes.
    • Acute inhalation LC₅₀ (rat) is between 500 mg/m³ and 3000 mg/m³ (4 hours); and
    • Globally Harmonised System of Classification and Labelling of Chemicals (GHS) category Acute Toxicity Cat 3.
• A Schedule 7 entry for carbon monoxide has also been proposed on the grounds that it meets the scheduling factors as outlined in the Scheduling Policy Framework^[143] as follows:
  • The substance has a high health hazard
    • Carbon monoxide presents a severe hazard from repeated and unprotected use or a significant risk of producing irreversible toxicity, which may involve acute, serious, or chronic health risks or even death if it is inhaled.
  • The dangers of handling the poison are such that special precautions are required in its manufacture, handling or use
    • The dangers associated with handling carbon monoxide are too hazardous for domestic use or use by untrained persons and warrant restrictions on its availability, possession or use.
  • The substance has a high potential for causing harm
    • Carbon monoxide should be available only to specialised or authorised users who have the skills necessary to handle it safely. Restrictions on its availability, possession, storage or use may apply.
  • Additional controls over access and training for substances in Schedule 7 may be required through inclusion in Appendix J
    • An Appendix J listing for carbon monoxide would restrict access to authorised or licenced persons. Carbon monoxide has the potential to cause severe and possible irreversible injury if an individual is exposed to high concentrations or a repeated dose. Limiting access to carbon monoxide could prevent the risk of misuse.
• The Schedule 7 record keeping requirements in Section 5 of the Poisons Standard will also provide a mechanism requiring the details of the order, purchaser and supplier and, depending on jurisdiction implementation, a record of a proof of purchaser authorisation. Under this schedule, the relevant records would be kept for a minimum period of five (5) years.

Current scheduling status

Carbon monoxide is not specifically scheduled in the current Poisons Standard.

Scheduling history

Carbon monoxide is not currently scheduled. However, it has been previously included in Appendix B (substances considered not to require control by scheduling).

In June 1991, the Drugs and Poisons Schedule Standing Committee (DPSSC) made a recommendation to delete the carbon monoxide entry from Appendix B. The Committee noted that carbon monoxide is a toxic gas and should not be classified as exempt from scheduling if it has not been considered.

Helium

Helium was also considered for scheduling in November 2017 by the Joint ACMS-ACCS due to its potential for misuse. The Committee recommended, and the Delegate agreed, that helium did not require scheduling.^[144] The Delegate found that there were many legitimate uses for helium, most of which were not related to domestic use in party balloons e.g. industrial, scientific and medical; and that helium was an inert, non-toxic gas and that the risk for helium do not exist unless it is deliberately inhaled resulting in oxygen deprivation leading to asphyxiation. The Delegate stated that correct and legitimate use of helium does not meet the scheduling criteria (SPF 2015).

Australian regulations

• Carbon monoxide is not included on TGA Database.^[145]
• Carbon monoxide is not included in any medicines currently active on the Australian Register of Therapeutic Goods (ARTG). This includes no prescription and no non-prescription medicines.
• Carbon monoxide is not permitted to be included in listed medicines as it is not included in the current Therapeutic Goods (Permissible Ingredients) Determination No.4 of 2019^[146].
• No results were found on the Prescribing medicines in pregnancy database^[147] for carbon monoxide.
• The Medicines Advisory Statement Specification 2019 (RASML No. 5)^[148] does not require warning statements pertaining to carbon monoxide as there is no product registered for therapeutic use.
• The Database of Adverse Event Notifications (DAEN)^[149] contains no reports of adverse events for products containing carbon monoxide as an active ingredient.
• There is one product that produces carbon monoxide listed on the Public Chemical Registration Information System Search (PubCRIS).^[150] The active constituents of this product include sodium nitrate and charcoal. After ignition of the cartridge, it produces the gas carbon monoxide. This product is used to poison foxes.
• The National Industrial Chemicals Notification and Assessment Scheme (NICNAS) undertook a human health tier II assessment in July 2014 on carbon monoxide^[151] as part of their Inventory Multi-tiered Assessment (IMAP) framework.
• Safe Work Australia has listed carbon monoxide in the Hazardous Chemical Information System (HCIS) with the current labelling and packaging requirements:^[152]
  • Carbon monoxide is required to be labelled with the signal word DANGER.
  • Carbon monoxide on the HCIS is under the following hazard categories; Flammable gas - category 1, Gasses under pressure, Reproductive toxicity - category 1A, Acute toxicity - category 3, and Specific target organ toxicity (repeated exposure) - category 1
  • Carbon monoxide is also required to have the following warning statements; H220 (Extremely flammable gas), H360D (May damage the unborn child), H331 (Toxic if inhaled), and H372 (Causes damage to organs through prolonged or repeated exposure).
  • Pictograms are required on the labels of hazardous chemicals used in the workplace. Carbon monoxide is required to be labelled with the following pictograms^[153]: GHS02, GHS04, GHS06, GHS08 (see Figure 1).
• The introduction to Poisons Standard states:

  Poisons which are packed and sold solely for industrial, manufacturing, laboratory or dispensary use are exempt from all labelling requirements included in the SUSMP as they are covered by labelling requirements under applicable jurisdictional Work Health and Safety laws, as amended from time to time. Note, however that this exemption does not extend to controls on supply of these poisons.

• State and Territory Legislation may have additional controls on the sale of potentially harmful substances. For example in Queensland, the Summary Offences Act 2005 Part 2 Offences (pdf,457kb) Section 23^[154] can apply to substances such as helium and nitrous oxide, but it does not apply to things the manufacturer intends to be ingested:

  23 Sale of potentially harmful things

  1. A seller must not sell a potentially harmful thing to another person if the seller knows or believes, on reasonable grounds, that the other person -
     1. intends to inhale or ingest the thing; or
     2. intends to sell the thing to another person for inhalation or ingestion whether by that person or someone else.

  Maximum penalty -

  1. 1. for a first offence - 25 penalty units or 3 months imprisonment; or
     2. for a second or later offence - 50 penalty units or 1 year's imprisonment.
  2. For the purposes of the Anti-Discrimination Act 1991, section 46, a seller is not to be taken to discriminate against a person only because the seller refuses to sell a potentially harmful thing to the person because of subsection (1).
  3. In this section -

     potentially harmful thing -

     1. means a thing a person may lawfully possess that is or contains a substance that may be harmful to a person if ingested or inhaled; and

        Examples -

        • glue
        • paint
        • a solvent
     2. includes methylated spirits; and
     3. does not include a thing intended by its manufacturer to be inhaled or ingested by a person using it.

International regulations

ECHA has published assessments for carbon monoxide. The toxicity assessments provided are in consideration of industrial workers as carbon monoxide is used widely in industrial processes. ECHA has not provided a toxicological summary in regards to the general population. ECHA states 'as the general population will not be exposed, DNEL [Derived No-Effect Level] considered unnecessary'.^[155]

ECHA has labelling requirements for carbon monoxide. ECHA states the following warning statements regarding carbon monoxide 'substance is toxic if inhaled, may damage the unborn child, causes damage to organs through prolonged or repeated exposure and is an extremely flammable gas'.^[156]

In Canada, the American Conference of Governmental Industrial Hygienists (ACGIH®) recommended the exposure limit for carbon monoxide to be 25 ppm TWA Biological Exposure Index.^[157]

The workplace exposure standard (WES) in New Zealand is 25 ppm and the short-term exposure limit (STEL) in Slovak Republic is 35 mg/m³ or 30 ppm. The American Conference of Governmental Industrial Hygienists (ACGIH) recommends a threshold limit value (TLV) of 25 ppm (29 mg/m³) TWA. This value is intended to maintain blood carboxyhaemoglobin (COHb) levels below 3.5 %, to minimise potential for adverse neuro-behavioural changes, and to maintain cardiovascular work and exercise capabilities.^[158]

The Safe Work Australia requirements for carbon monoxide are in line with both the ECHA regulations and with the regulations provided on the Canadian Centre for Occupational Health and Safety website.^[159],^[160]

Current use in Australia

Carbon monoxide has many industrial uses in Australia, including^[161] (but not limited to):

• Processing aids (including the smoking and colour fixture of some meats);^[162]
• Manufacture of chemicals, metal and plastic products, metal surface treatment products, polymers and semiconductors;
• Manufacturing intermediates;
• Sewage treatment;
• Present in fuels, metal surface treatment products, polymers, laboratory chemicals etc.; and
• As a calibration gas.^[163]

There is also emerging literature to suggest therapeutic uses for carbon monoxide; clinical trials are currently investigating therapeutic roles.^[164]

Summary of pre-meeting public submissions

In response to the notice published under regulation 42ZCZK advising of the proposed amendment, three (3) submissions were received. One (1) submission supported the amendment and two (2) submissions opposed the amendment.

The main points in support of the proposed amendment were:

• Since January 2014, NSW PIC has received 185 calls regarding deliberate self-poisoning exposures to carbon monoxide.
• Whilst these calls have involved exposures to carbon monoxide from car exhaust fumes, other motor or generator fumes and charcoal burners (rather than inhalation from carbon monoxide canisters), NSW PIC believes the number of calls received indicates that carbon monoxide continues to be an option for deliberate self-poisoning and they strongly support the proposed scheduling.

The main points in opposition of the proposed amendment were:

• The proposal could impose significant trading barriers and regulatory consequences throughout the economy.
• Carbon monoxide is not a product that is supplied to the domestic market. Scheduling is inappropriate or unnecessary.
• Carbon monoxide has legitimate uses for industrial purposes only and the risk management control is legislated by workplace laws.
• Carbon monoxide is present at very low levels in the atmosphere. Under the proposed Schedule 7, there is no cut-off threshold, therefore any product with an atmospheric headspace in its packaging would technically be considered a Dangerous Poison. This has the inadvertent potential to remove a significant proportion of products from the marketplace and must be avoided.
• Common applications for carbon monoxide include:
  • Lung function test - typically 0.3% in a mixture of various other gases, very common;
    • Quench gas for polymerisation reactions (as a kind of 'safety station') - pure;
    • Ore analysis for iron mines - pure;
    • Calibration gases - typically 5 ppm through to a few percent. Rarely >5%;
    • Modified Atmosphere Packaging (MAP) in food applications, some customers choose to buy pure and mix-on-site and some prefer the safer option of buying a premix at 5% carbon monoxide;
    • Laser resonator gas mixtures - typically low %; and
    • 'Bump testing' use in confined space entry or for industrial hygiene applications - in these circumstances customers typically use products with concentrations ranging from 20ppm through to 1000 ppm.
  • XXXXXX has initiated its own product stewardship guidelines that will impose barriers to obtaining the product and the guidelines are currently being implemented by members. The guidelines that XXXXXX members have agreed to implement in relation to carbon monoxide and any gas mixture containing 5% or greater carbon monoxide, will not allow supply without a written end user declaration from the purchaser outlining the intended uses for the product, where the product will be used and delivered to and who the product is intended for.
  • The XXXXXX members are also providing training and support to customer service staff to identify when a sale may be suspicious and if the declared use is not legitimate.
  • The industry believes that the most effective and efficient means of controlling the access and use of these products is through the consistent implementation of agreed guidelines that consider the risk profile of the product.
  • Inclusion in Schedule 7 will add significant cost throughout the industry, on a wide-ranging list of products. Under Schedule 7, simple products that pose no health risk, such as air or oxygen, will have full schedule 7 controls applied.

Summary of ACCS advice/recommendations to the Delegate

The Committee recommended that on balance, carbon monoxide does not require a schedule listing.

Members agreed that the relevant matters under Section 52E(1) of the Therapeutic Goods Act 1989 included (a) risks and benefits of the use of a substance; (b) the purpose for which a substance is to be used and the and extent of use; (c) the toxicity of a substance; (d) the dosage, formulation, labelling, packaging and presentation of a substance; (e) the potential for abuse of a substance; and (f) any other matters that the Secretary considers necessary to protect public health.

The reasons for the advice included:

52E(1) Considerations	Reasons
a - the risks and benefits of the use of a substance	Risks CO is an odourless, colourless, toxic gas that can cause hypoxic tissue damage and death. The public health risks for CO occur through deliberate misuse. Benefits CO has a number of legitimate uses, mainly in industrial settings.
b - the purposes for which a substance is to be used and the extent of use of a substance	CO products have a number of industrial uses but are not intended for domestic use. Uses include CO as a processing aid and in the manufacture of chemicals (including formaldehyde and synthetic methanol), metals and plastic products, also as a fuel/fuel additive.
c - the toxicity of a substance	CO binds to haemoglobin with stronger affinity than oxygen. At low concentrations, CO causes mild symptoms like headache, dizziness. At higher concentrations, CO causes loss of consciousness and hypoxic damage to tissues e.g. CNS, cardiovascular system, death. CO is particularly toxic to pregnant women/foetus, people with underlying cardiovascular disease. The toxicity of CO is dose, concentration and duration dependent.
d - the dosage, formulation, labelling, packaging and presentation of a substance	CO is packaged in containers intended only for industrial use and is not sold to the public.
e - the potential for abuse of a substance	There is potential for intentional misuse but measures are in place to prevent public access to CO products. Misuse potential: suicide/homicide through CO inhalation.
f - any other matters that the Secretary considers necessary to protect public health	Industry initiatives to further prevent the accessibility of CO products to the public are supported. Some emerging reports of therapeutic use - if these were established a Schedule 4 entry could be considered.

Delegate's considerations

In making this interim decision, I have considered the following material:

• The application to amend the current Poisons Standard with respect to carbon monoxide;
• Advisory Committee on Chemicals Scheduling's advice;
• Section 52E of the Therapeutic Goods Act 1989, in particular (a) the risks and benefits of the use of a substance; (b) the purposes for which a substance is to be used and the extent of use of a substance; (c) the toxicity of a substance; and (d) the dosage, formulation, labelling, packaging and presentation of a substance.
• The Australian Health Ministers' Advisory Council's Scheduling Policy Framework (SPF 2018); and
• Scheduling Handbook (V 1.1, July 2019).

Reasons for the interim decision

I agree with the Committee's finding that the relevant provisions of section 52E of the Therapeutic Goods Act 1989 are (a) the risks and benefits of the use of a substance; (b) the purpose for which a substance is to be used and the and extent of use of a substance; (c) the toxicity of a substance; (d) the dosage, formulation, labelling, packaging and presentation of a substance; (e) the potential for abuse of a substance; and (f) any other matters that the Secretary considers necessary to protect public health.

In my view, the relevant parts of the SPF 2018 are the Scheduling Factors for Schedules 6 and 7.

I have made an interim decision not to amend the current Poisons Standard in relation to carbon monoxide in the terms stated in the proposal as a balance, carbon monoxide does not require control by Scheduling. I have set out my reasons below.

Carbon monoxide is an odourless, colourless gas that binds to haemoglobin with a stronger affinity than oxygen. Carbon monoxide meets the acute inhalation (LC₅₀ (rat) of 1489 mg/m3 is between 500 mg/m³ and 3000 mg/m³, 4-hour exposure) toxicological endpoint and Globally Harmonised System (GHS) of Classification and Labelling of Chemicals category, Acute Toxicity Category 3 under the SPF Schedule 6 Scheduling Factors.

I have taken into account that carbon monoxide meets some of the Schedule 7 Scheduling Factors, including having a high toxicity potential, which may cause death or severe injury (due to hypoxic tissue damage) if inhaled. The toxicity of carbon monoxide is dose, concentration and duration dependent. Furthermore, carbon monoxide has the potential to cause harm and warrants restriction on its availability to specialised or authorised users who have the skills necessary to handle it safely. I acknowledge that carbon monoxide has a known potential for misuse and that evidence of deliberate misuse has been reported in suicide attempts and homicide, but overwhelming from sources other than from cylinders or canisters containing carbon monoxide. I have also considered the original proposal regarding additional controls to access and training for carbon monoxide through inclusion in Appendix J.

Having turned my mind to the toxicological and hazard profiles of carbon monoxide as outlined above, I find that on balance, although carbon monoxide is a hazardous substance that meets some of the Scheduling Factors for Schedules 6 and 7, it does not require a schedule listing on the basis that there are no products where high concentrations of carbon monoxide (in canisters or cylinders) are sold to the public for legitimate domestic uses. Legitimate uses of high concentration carbon monoxide are very specialised, with uses predominately limited to industrial purposes. I find that on balance, the risk of public exposure to carbon monoxide from pressurised canisters or cylinders is very low and is more appropriately regulated by industry controls. Further to this, I note the claims made in the public submissions that industry is currently implementing further controls aimed at preventing public access to carbon monoxide products. Having considered the Committee's advice regarding consultation with the jurisdictions to determine additional controls to limit access to authorised or licenced personnel and mandate training via inclusion in Appendix J, as carbon monoxide does not meet all of the Scheduling Factors for Schedule 7, further consideration around an Appendix J are not relevant at this time.

I note that previous consideration by the Delegate and Committee of another gas (helium) in pressurised gas canisters or cylinders in 2017-2018 (ACCS/ACMS #17), did not result in the scheduling of this substance. While helium's deliberate misuse through inhalation leading to oxygen deprivation and asphyxiation could pose a risk to humans, the substance is actually an inert, non-toxic gas that has many legitimate uses including industrial, scientific and medical uses. In addition, a small amount of helium is available for domestic use. The latter allows for general public to access helium in pressurised gas canisters or cylinders for legitimate reasons e.g. inflation of balloons. On the other hand, while carbon monoxide is NOT an inert, non-toxic gas; it does not have any legitimate uses in domestic settings, and is not accessible by the general public. I agree with the current Committee's view (ACCS #26) that access by the general public to pressurised gases in canisters or cylinders would be a key driver for a substance to be considered for scheduling under the Poisons Standard.

I am satisfied that at this time, carbon monoxide does not meet the requirements for inclusion in the Poisons Standard. The risk profile of carbon monoxide is largely mitigated by other regulations in industry and on balance, as carbon monoxide containing-products are not supplied to the public in the domestic market, public risk exposure is low. I have considered that there are some emerging reports of therapeutic use for carbon monoxide and if these were established, a Schedule 4 entry could be considered in the future.

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