Coal Inspectorate | Bulletin | No.221 V 1 | 14 May 2024

Coal mine worker loses consciousness following the inhalation of nitrogen supplied through an air-line helmet respirator

What happened?

A coal mine worker (CMW) lost consciousness following the inhalation of nitrogen supplied through an air-line helmet respirator.

How did it happen?

• On 26 April 2024, a contractor boilermaker (CMW), was setting up for a hot work task and attached their air-line welding helmet respirator to the nitrogen line (refer Figure 1).
• The CMW then put on their air-line welding helmet and fell to the ground.
• Other CMWs in proximity saw the worker fall and went to their aid.

Key issues

• The CMW inhaled nitrogen through their air-line welding helmet respirator.
• Boilermakers are often tasked with connecting air-line welding helmet respirators to compressed air lines.
• Nitrogen lines at this site location were previously charged with compressed air.
• The fittings on the nitrogen lines are the same as the air-line helmet fittings.
• Air-line helmet respirators are not authorised for use in this part of the workplace.
• The nitrogen supply pipework was clearly labelled as being nitrogen.
• Reliance on administrative controls was ineffective.

Recommendations

1. Apply change management processes to identify hazards and manage risks when substituting one type of ‘hazardous chemicals and dangerous goods’, with another.
2. Investigate all work areas to identify the hazard of having gas lines present containing irrespirable air (e.g. nitrogen), where air-line respirators including weld helmets may be used.
3. Do not rely on administrative controls and adopt higher order controls that prevent incorrect gas supplies being used.
4. Provide compressed air supply lines where air-line respirators including weld helmets are likely to be used.
5. Consider using different connections for nitrogen lines and compressed air lines.
6. Ensure gas lines are clearly labelled at both the supply and at the connection point of use.
7. Review supervision requirements of contract CMWs to ensure they are familiar with work areas and site requirements.
8. Ensure CMWs undertake a review of hazards in their work area prior to undertaking hot work.
9. Ensure respiratory protection equipment (RPE) training is provided to all CMWs required to wear respirators, including air-line respirators for boilermakers, and is aligned with AS 1715.

References and further information

AS/NZS 1715:2009 ‘Selection, use and maintenance of respiratory protective equipment’.