Mixing of cleaning chemicals

  • Safety Flash
  • Published on 22 July 2022
  • Generated on 26 July 2026
  • IMCA SF 18/22
  • 2 minute read

A worker was exposed to chemical vapours which resulted in breathing discomfort.

What happened?

A worker mixed bleach and toilet cleaner whilst working in the confines of a toilet area onboard a tug. The two chemicals mixed and there was a chemical reaction.  As a result the worker was exposed to chemical vapours which resulted in breathing discomfort. Onboard medical treatment was required, followed by onshore cautionary medical assessment. The worker was diagnosed with Chemical Bronchitis.

What went right?

  • Use of Ship Captains Medical Guide for guidance on treatment onboard.
  • Promptly contacting emergency medical contact for medical advice.
  • Promptly sending the employee for cautionary medical assessment ashore.
  • Full support provided by shore-based management.

What went wrong?

Investigation revealed that the employee involved had no awareness of the consequences of mixing these chemicals.

  • Routine activity without thought.
  • Lack of training, lack of knowledge.
Mixing of cleaning chemicals safety poster

Lessons learned and actions taken in this case

It was realised that the company focus on chemicals awareness was directed more on industrial chemicals with a limited focus on domestic chemicals. Actions were taken:

  • Training materials were provided regarding domestic chemicals.
  • Risk assessments were updated with regard to the mixing of chemicals.
  • There was a review of domestic and industrial chemical stocks, ensuring stock management and seeking to minimise the number of chemicals held onboard.
  • Access to all chemicals (industrial and domestic) should be controlled.

Latest Safety Flashes:

MAIB: Catastrophic engine failure and subsequent fire

MAIB has published Accident Investigation Report 10/2026 into a catastrophic failure of a diesel generator engine on board the vessel Kommandor Susan.

Read more
BSEE: Compressed gas cylinder hazards

BSEE has published Safety Alert 516, relating to potential risks involving compressed gas cylinders.

Read more
MSF: dropped object inside vessel tank

MSF have published Safety Alert 26-05 relating to a tank cleaning machine coming lose and falling within a tank on a vessel.

Read more
Uncontrolled movement of cargo

During offshore cargo operations alongside a rig, a single pipe loaded on deck shifted due to vessel motion and swell conditions.

Read more
Positives – rubber seals on hatches, securing of shackle pins, fuel sample box

A Member reports a few positive findings.

Read more

IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of the entire offshore industry.

The effectiveness of the IMCA Safety Flash system depends on the industry sharing information and so avoiding repeat incidents. Incidents are classified according to IOGP's Life Saving Rules.

All information is anonymised or sanitised, as appropriate, and warnings for graphic content included where possible.

IMCA makes every effort to ensure both the accuracy and reliability of the information shared, but is not be liable for any guidance and/or recommendation and/or statement herein contained.

The information contained in this document does not fulfil or replace any individual's or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.

Share your safety incidents with IMCA online. Sign-up to receive Safety Flashes straight to your email.