Coal Inspectorate | Alert | No.393 V 1 | 02 July 2021

Workers became unresponsive and rescued from dragline after spray painting inside confined space

What happened?

On 25 April 2021, while working on a dragline shutdown and performing spray painting activities under a Confined Space Entry Permit, a Coal Mine Worker (CMW) became unresponsive and was rescued from inside the revolving frame of a dragline. A second CMW also had to be rescued after they re-entered the confined space to assist with the first rescue.

The investigation into the incident has found the following matters that are relevant for the attention of industry, there having been previous similar confined space incidents associated with dragline shutdowns and other confined work activities requiring attention by industry.

How did it happen?

• While spray paint was being applied to two separate work fronts inside the revolving frame of the dragline, airborne solvent vapours released by the paint accumulated inside the confined space.
• One of the workers who was assisting a spray-painter with hose lines was overexposed to the solvent vapours and became unresponsive.
• The spray painter and another worker from inside the space were having difficulty lifting the affected CMW out through the access way, when another spray painter who had previously exited the space, re-entered the confined space to assist with the rescue.
• The spray painter who re-entered the confined space was not wearing any respiratory protection at the time and was also overexposed to the solvent vapours, became unresponsive and required assistance to exit the space.
• Both of the workers recovered a short time after being removed from the confined space and were relocated outside in fresh air. Affected workers were transported to hospital for medical assessment and released a short time later without any diagnosed health effects attributed to the exposure event.

Key issues

• Ventilation was not applied to the confined space to dilute or remove airborne contaminants generated by spray painting, although ventilation was identified as a control on the Confined Space Entry Permit and in the Safety Data Sheet (SDS) for the paint product. Ventilation had been applied previously for other work conducted inside the revolving frame during the dragline shut down and ventilation equipment was readily available at the time of the incident.
• Respiratory protection worn by the affected CMW did not provide an adequate level of protection. Although the spray painters wore air-supplied respiratory protection connected to a compressed airline, the hose line assistants used negative pressure half-face respirators with cartridge-style filters. The protection provided by negative pressure respirators is significantly lower than for air-supplied respirators and is dependent on individual facial fit, filter breakthrough capacity and the timely replacement of filters.
• The second CMW had removed their air-supplied respirators on exiting the space earlier and was not wearing any respiratory protection when they re-entered the confined space to assist with the rescue.
• Personal gas detectors used to monitor atmospheric contaminants inside the confined space were not suitable for detecting the solvent vapours produced by spray painting.
• The confined space entry permit was issued by a CMW who was not authorised to issue the permit. The confined space entry permit was issued without inspection of the area to verify that protective controls identified on the permit had been implemented. The JRA which was completed for work to be conducted inside the confined space, required an amendment to include task-specific controls for spray painting, although these controls were not communicated through the confined space entry permit process.
• The paint product used at the time of the incident was chosen as a substitute as the paint normally used was not able to be supplied. The substitute product was not approved for use at the mine and the SDS indicated it contained significantly higher proportions of solvent ingredients compared to the other product normally used.

Recommendations

All mine SSEs should:

1. Review site procedures for confined space entry to ensure:
• Roles and responsibilities are clearly defined, relevant competencies are assigned to each and these are clearly communicated to all persons working in confined spaces
• The confined space entry permit adequately reflects and is capable of incorporating task-specific risks and controls identified in any accompanying risk assessments, for the full duration of the permit.
• The issue of confined space entry permits are conditional on the completion of a pre-inspection to verify that all relevant controls and conditions identified on the permit have been implemented.
• Emergency response plans include provision for rescue and recovery of unresponsive individuals from inside confined spaces and these are documented on the confined space entry permit.
2. Ensure persons required to wear respiratory protection have been trained in the selection, use and maintenance of respiratory protection in accordance with AS/NZS 1715-2009. In addition, persons required to wear negative pressure respirators to complete facial fit testing and trained in the limitations and replacement requirements for particulate and gas filter media.
3. Ensure ventilation controls are applied to all spray painting tasks to be performed inside confined spaces, irrespective of duration.
4. The selection of gas detectors for use in confined space entry work should consider the type of contaminants likely to be present and cause an exposure risk to workers inside the space.