4,4'-Methylene bis(2-chloroaniline) [101-14-4] (MOCA) compliance campaign

Between October 2023 and August 2024, Workplace Health and Safety Queensland (WHSQ) audited businesses who were using, handling, storing or supplying 4,4'-Methylene bis(2-chloroaniline) [101-14-4] (MOCA).

The campaign was undertaken to ensure persons conducting a business or undertaking (PCBUs) supplying, using, handling or storing MOCA were complying with requirements of the Work Health and Safety Regulation 2011 (WHS Regulation) and eliminating or minimising (so far as is reasonably practicable) risks of worker exposure.

Background

MOCA is classified as a restricted carcinogen in Schedule 10 of the WHS Regulation.

MOCA is a Category 1B carcinogen, presumed to cause cancer in humans.

Uses - primary use is as a curing agent for isocyanate-based polyurethane products (for example, industrial tyres, rollers and gaskets).
Health risks - occupational exposure occurs primarily through skin absorption (ingestion and inhalation are also possible). MOCA is structurally similar to benzidine (a known bladder carcinogen) and is associated with bladder cancer in humans.
Legislation - PCBUs cannot use, handle, or store MOCA without an authorisation or exemption from the Regulator. Suppliers must not supply MOCA without evidence of such authorisation.

Campaign overview

The campaign targeted the supply, use, handling and storage of MOCA. The campaign scope involved:

review of authorised MOCA users
verification of supplier compliance
identification of unauthorised users
inspection of storage locations.

Campaign snapshot

12 authorisations were reviewed.
In total eight Queensland based PCBU’s were supplied with MOCA without authorisation between 2012 and 2024.
Four suppliers of MOCA that had been recorded through authorisation applications to OIR were interviewed and verified that they understood their obligations under the WHS Regulation 2011. Conversations with suppliers revealed that, as suppliers had no capacity for storage in Queensland, third party storage facilities were engaged to store MOCA on their behalf.
Four facilities were identified as storing MOCA in Queensland.

Enforcement actions and regulatory response

Audit planning – identify MOCA holders and suppliers
Onsite inspections – assess handing, storage and controls
Compliance assessment – verify WHS Regulation adherence
Risk mitigation – recommend controls to reduce exposure
Enforcement and follow-up – actions, guidance and rechecks.

The campaign prompted the following actions:

two show causes
four Section 155 notices
two Section 171 notices
one infringement notice
three prohibition notices
46 improvement notices.

Campaign phases

Phase 1: Authorisation holder assessments

A WHSQ advisor from the Occupational Health, Hygiene and Asbestos Unit (OHHA) and a WHSQ inspector from Compliance and Field Services (CFS) conducted unannounced site visits to all authorisation holders.

Key findings

At the start of the campaign, 12 businesses held authorisations. The audits revealed significant changes in some operations and risk profiles.

Change in risk

The operation of 10 authorisation holders had changed in a manner that altered the risk level to workers, including increased quantities of MOCA

Major amendments required

10 amendment applications were processed to address these changes.

Cancellations

One authorisation was cancelled after the user confirmed they no longer use MOCA.

One business was no longer operating.

Show cause

Two businesses were required to ‘show cause’ as to why their authorisation should not be cancelled due to safety standards:

One business improved standards and was approved with strict conditions.

One business ceased operation.

Phase 2: Suppliers

The campaign identified four suppliers retailing MOCA in Queensland. Notices under section 155 of the WHS Regulation were served to all suppliers to obtain supply records.

Unauthorised supply - records indicated that suppliers had provided MOCA to PCBUs that did not hold an authorisation. Two suppliers provided MOCA to eight unauthorised PCBUs.
Third party storage -suppliers with no physical presence in Queensland utilised third-party logistics for storage.

Findings - these storage facilities had limited knowledge of what was being stored or how to manage potential spills.

Outcome - three facilities have ceased storing MOCA due to the intervention, while one facility has improved its safety systems and continues to store MOCA on behalf of others.

Phase 3: Unauthorised users

The audit of supplier records identified eight Queensland-based PCBUs supplied with MOCA without authorisation between 2012 and 2024.

Active unauthorised use - four PCBUs were found to be actively using MOCA without authorisation.
Transition to alternatives - following the stop of supply by the supplier, all unauthorised users have stopped MOCA use or replaced it with a non-carcinogenic alternative.
Benefits of substitution - users reported that the alternative product performed well, required less usage, did not require heating, and eliminated worker exposure to restricted carcinogens.

Outcomes

The MOCA compliance campaign strengthened workplace safety, eliminated unauthorised supply, and promoted the adoption of safer alternatives across PCBUs. These improvements will require ongoing awareness, rigorous WHS compliance, and proactive risk management to prevent exposure to carcinogens.

Cessation of unauthorised supply - supply of MOCA to PCBUs without authorisation from the regulator has ceased.
Risk reduction - significant improvements in safety standards and legislative compliance among authorisation holders has reduced worker exposure risks, supported by improved control measures.
Third-party safety - a reduction in the use of third-party storage facilities and improved safety systems.
Alternative products - substitution of MOCA with safer alternatives has significantly reduced potential worker exposure to restricted carcinogens.