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Scheduling delegate's interim decisions and invitation for further comment: ACCS/ACMS, March 2016

Scheduling medicines and poisons

12 May 2016

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1.17 Potassium hydroxide and sodium hydroxide

Part A - Interim decisions on scheduling proposals referred to an advisory committee (March 2016)

1. Advisory Committee on Chemicals Scheduling (ACCS#16)

1.17 Potassium hydroxide and sodium hydroxide

Referred scheduling proposal
  • Amend the existing Schedule 6 or 10 entries to address possible ambiguities in the duplication of the exception clause c) that relates to liquid or semi-solid food additive preparations, the pH of which is more than 11.5, for domestic use.
Scheduling application

On 30 November 2015 the Chemicals Scheduling Delegate identified ambiguity in the current entries for sodium and potassium hydroxide in relation to the use in food additive preparations. The proposal is to delete the exception clause c) in the Schedule 6 entries for potassium hydroxide and sodium hydroxide.

The reason for the request is:

  • The Schedule 10 entry prohibits use as a food additive except where in Schedule 6; however the Schedule 6 entry excludes the use as a food additive ingredient.
Specific issues/questions raised by the delegate

In previous versions of the SUSMP, listing in Appendix C was used to designate specific uses of substances that should be prohibited. The previous heading of Appendix C was:

SUBSTANCES, OTHER THAN THOSE INCLUDED IN SCHEDULE 9, OF SUCH DANGER TO HEALTH AS TO WARRANT PROHIBITION OF SALE, SUPPLY AND USE.

In some cases, this message was directed to the relevant regulatory agency (e.g. TGA for therapeutic uses), while it is understood that some State/Territory jurisdictions automatically applied controls analogous to those of Schedule 7 to control those uses of substance listed in Appendix C.

Previous versions of the Poisons Standard (SUSMP4 and 5, 2013-2014) used a 'dagger' to designate substances in Schedules 4, 5 and 6 that were also listed in Appendix C, with a page header that drew attention to those listings ('Substances marked † are listed in Appendix C'). When Appendix C was transitioned to Schedule 10 in SUSMP6 (2015), the 'dagger' designation was discontinued. Instead, exception clauses were added to Schedule 10 listings for substances where the primary listing was in Schedules 4, 5 or 6. The addition of these exception clauses was designed to follow the 'cascading principle' where listing of a substance in the most restrictive schedule is used as the primary listing, with cross-references to listings in other less restrictive schedules designated by exception clauses.

The delegate is concerned that the cascading principle may be inappropriate for substances listed in Schedule 10, that was intended to apply quite selective controls, and that the use of exception clauses in Schedule 10 could introduce ambiguities. The concerns about possible ambiguities are spelled out in the delegate questions.

  • The current Schedule 10 entries for sodium and potassium hydroxides are intended to prohibit the use of these substances in food additive preparations for domestic use, where the pH exceeds 11.5. The current S6 entries also contain an exemption clause (c) for the same use. Does the ACCS agree that the exception clauses added to the Schedule 10 entries for sodium and potassium hydroxide are potentially ambiguous (they were not included in previous versions of the Appendix C entry) and that having identical exception clauses in both entries is anomalous, apparently cancelling each other out?
  • Does the ACCS agree that deletion of the exception clauses in the Schedule 10 entries will fix the ambiguity? [Note that similar concerns could also be applied to the ALKALINE SALTS entries in Schedule 5, 6 and 10].
  • If it is impractical to re-introduce the 'dagger' system of identifying substances in Schedules 4, 5 and 6 that are also listed in Schedule 10, does the ACCS consider that re-introducing a page header for these schedules that could draw attention to possible listing in a more restrictive schedule. Such wording could be 'Substances in this schedule may also be listed in Schedule 10, where additional restrictions may be applied. Readers are urged to consult the index for other listings'. Alternatively, the heading of Schedule 10 could include words like: 'Listing in Schedule 10 imposes restrictions additional to those that may result where the substance is listed in other schedules. Readers are urged to consult the index for other listings'.
Substance summary

Please refer to the NICNAS assessment reports for sodium hydroxide and potassium hydroxide available on the NICNAS website.

Current scheduling status

Sodium hydroxide and potassium hydroxide are currently listed in Schedules 5, 6 and 10 of the SUSMP. They are also included in Appendix E and F.

Schedule 5

POTASSIUM HYDROXIDE (excluding its salts and derivatives) in preparations containing 5 per cent or less of potassium hydroxide being:

  1. solid preparations, the pH of which in a 10 g/L aqueous solution is more than 11.5; or
  2. liquid or semi-solid preparations, the pH of which is more than 11.5 except in food additive preparations for domestic use.

SODIUM HYDROXIDE (excluding its salts and derivatives) in preparations containing 5 per cent or less of sodium hydroxide being:

  1. solid preparations, the pH of which in a 10 g/L aqueous solution is more than 11.5; or
  2. liquid or semi-solid preparations, the pH of which is more than 11.5 except in food additive preparations for domestic use.

Schedule 6

POTASSIUM HYDROXIDE (excluding its salts and derivatives) except:

  1. when included in Schedule 5;
  2. in preparations containing 5 per cent or less of potassium hydroxide being:
    1. solid preparations, the pH of which in a 10 g/L aqueous solution is 11.5 or less; or
    2. liquid or semi-solid preparations, the pH of which is 11.5 or less; or
  3. in liquid or semi-solid food additive preparations, the pH of which is more than 11.5, for domestic use.

SODIUM HYDROXIDE (excluding its salts and derivatives) except:

  1. when included in Schedule 5;
  2. in preparations containing 5 per cent or less of sodium hydroxide being:
    1. solid preparations, the pH of which in a 10 g/L aqueous solution is 11.5 or less; or
    2. liquid or semi-solid preparations, the pH of which is 11.5 or less; or
  3. in liquid or semi-solid food additive preparations, the pH of which is more than 11.5, for domestic use.

Schedule 10

POTASSIUM HYDROXIDE (excluding its salts and derivatives), in liquid or semi-solid food additive preparations, for domestic use, the pH of which is more than 11.5.

SODIUM HYDROXIDE (excluding its salts and derivatives), in liquid or semi-solid food additive preparations, for domestic use, the pH of which is more than 11.5.

Relevant scheduling history

Potassium and sodium hydroxides were first considered for scheduling at the May 1956 and January 1955 meetings, respectively. They have since been considered a number of times, most recently at the February 2010 meeting. At this meeting the Committee discussed the inherent properties of lye water and its poisoning risk – particularly consequences of accidental ingestion by children. It was noted that the lye water accidental poisoning issue was considered at previous meetings and at that time the Committee had decided that the risks from lye water with a pH of more than 11.5 were adequately addressed through a CRC requirement (along with public education and labelling). Several Members asserted that the information now before the Committee was sufficient to establish that this existing level of control had not been sufficient, noting lye water accidental ingestions and injuries had continued to occur since the mandating of CRCs.

Members generally agreed that, for lye water preparations with a pH of more than 11.5, the extremely alkaline nature, even in small amounts, could cause life threatening caustic injuries. A Member noted, however, that the risk of ingestion was most significant with regard to use in the domestic setting. The Member argued that there appeared to be scope for continuing to allow non-domestic access (such as restaurants or industrial food processing) to high strength lye water products. Another Member noted that there appeared to be alternative preparations available with pH of 11.5 or less which should be sufficient for domestic use. The Committee therefore agreed to restrict the domestic availability of lye water by capturing domestic food additive preparations, with pH of more than 11.5, through specific entries to this effect for alkaline salts, sodium hydroxide and potassium hydroxide in Appendix C.

Pre-meeting public submissions

One public submission was received. That submission supported the proposed amendments to remove ambiguity in those entries. The submission provided suggested wording for the revised entry.

The public submissions are available at: Public submissions on scheduling matters.

ACCS advice to the delegate

In response to the Delegate's request, the Committee have advised that the KOH and NaOH entries are ambiguous, and that amendment to the Schedule 6 entries would provide greater clarity.

The Committee advised that, with the availability of an electronic version of the SUSMP it was now easy for users to do a search of the document to find all relevant entries and inserting a dagger was now unnecessary.

The Committee recommended that the current Schedule 6 entries for potassium hydroxide and sodium hydroxide be amended as follows:

Schedule 6 - Amend entry

POTASSIUM HYDROXIDE (excluding its salts and derivatives) except:

  1. when included in Schedule 5 or 10; or
  2. in preparations containing 5 per cent or less of potassium hydroxide being:
    1. solid preparations, the pH of which in a 10 g/L aqueous solution is 11.5 or less; or
    2. liquid or semi-solid preparations, the pH of which is 11.5 or less; or

SODIUM HYDROXIDE (excluding its salts and derivatives) except:

  1. when included in Schedule 5 or 10; or
  2. in preparations containing 5 per cent or less of sodium hydroxide being:
    1. solid preparations, the pH of which in a 10 g/L aqueous solution is 11.5 or less; or
    2. liquid or semi-solid preparations, the pH of which is 11.5 or less

The Committee recommended an early implementation date (1 October 2016).

The matters under subsection 52E(1) of the Therapeutic Goods Act 1989 considered relevant by the Committee included: f) Amendment further clarifies existing entries.

Delegate's considerations

The delegate considered the following in regards to this proposal:

  • Scheduling proposal;
  • Public submissions received;
  • ACCS advice;
  • Section 52E of the Therapeutic Goods Act 1989;
  • Scheduling factors17;
  • Other relevant information.
Delegate's interim decision

The delegate notes, and accepts, ACCS advice to amend the Schedule 6 entries for sodium and potassium hydroxides, since they appeared to contain an exemption clause that contradicts the purpose of the Schedule 10 entry. The purpose of the Schedule 10 entries was to prevent the availability of such strongly alkaline solutions for use as food additives in the domestic market. The proposed cross-reference in the Schedule 6 entries to the entries in both Schedules 5 and 10 should clarify the intent of these controls. The delegate notes that the proposed amendments are supported by the submission from industry.

The proposed implementation date is 1 October 2016. This is a clarification of existing schedule entries, so it should be implemented in the earliest revision of the Poisons Standard.

The delegate considered the relevant matters under section 52E (1) of the Therapeutic Goods Act 1989: (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.

Schedule 6 - Amend entry

POTASSIUM HYDROXIDE (excluding its salts and derivatives) except:

  1. when included in Schedule 5 or 10; or
  2. in preparations containing 5 per cent or less of potassium hydroxide being:
    1. solid preparations, the pH of which in a 10 g/L aqueous solution is 11.5 or less; or
    2. liquid or semi-solid preparations, the pH of which is 11.5 or less; or

SODIUM HYDROXIDE (excluding its salts and derivatives) except:

  1. when included in Schedule 5 or 10; or
  2. in preparations containing 5 per cent or less of sodium hydroxide being:
    1. solid preparations, the pH of which in a 10 g/L aqueous solution is 11.5 or less; or
    2. liquid or semi-solid preparations, the pH of which is 11.5 or less

Footnotes

  1. Scheduling Policy Framework for Medicines and Chemicals (SPF, 2015)

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