Investigation reveals systemic failures behind catastrophic tyre blast that injured two workers at NSW quarry

A catastrophic tyre explosion that seriously injured two quarry workers was caused by a structural failure in the sidewall of a truck tyre and a series of systemic safety lapses, according to a detailed investigation released by the NSW Resources Regulator.

The incident occurred on 8 February 2024 at Clovass Quarry near Casino, in the Northern Rivers region of New South Wales. Two truck drivers were inflating a removed tyre using a workshop tyre-fitting machine when the sidewall of the tyre violently ruptured - a failure known as a "zipper failure" - releasing compressed air and debris in a high-pressure blast.

One worker was thrown to the ground with sufficient force to tear off his shirt. He suffered perforated ear drums, hearing loss, and upper-body abrasions, while the second worker sustained eye injuries from rubber and steel fragments and is experiencing ongoing tinnitus.

Tyre weakened by prior underinflation or flat running

The Regulator’s investigation found the failure was likely due to the tyre having previously been operated while underinflated or flat, damaging its structural integrity over time. Zipper failures, the report explained, occur when weakened sidewall belts rupture under inflation pressure - in this case, while no protective barrier or remote inflation system was in use.

Alarming safety shortfalls identified

The report revealed multiple failures in risk management, engineering controls, and training at the quarry, operated by Holmes’s Pty Ltd. These included:

• No written procedures or formal risk assessment for inspecting and inflating tyres

• Lack of protective tyre cages or remote-pressure control systems to protect against blast hazards

• Absence of exclusion zones, placing workers in the line of fire during inflation

• Workers not wearing mandated PPE, such as hearing and eye protection

• Inadequate training to detect tyre damage, including signs of compromised sidewalls

Notably, the compressed air system lacked a remote dump valve, pressure gauge, or digital inflation control, meaning workers had no safe means of monitoring or controlling pressure levels from a distance.

Company enters WHS undertaking

Following the investigation, Holmes’s Pty Ltd has entered into a Work Health and Safety undertaking with the regulator. In response to the findings, the company has installed a tyre inflation cage and updated inflation systems in line with industry guidelines, as shown in post-incident images included in the report.

Regulator issues comprehensive safety recommendations

The Resources Regulator has called on all quarry and mine operators to immediately reassess their tyre maintenance procedures, issuing clear recommendations:

• Implement remote-controlled inflation systems with pressure monitoring

• Use tyre cages or restraining devices

• Establish and enforce physical exclusion zones during inflation

• Ensure tyres suspected of damage are fully deflated, removed, and internally inspected before reuse

• Train workers to identify signs of structural tyre damage, including bulges, exposed cords, or internal cracking

The regulator also urged adherence to PPE policies and compliance with existing standards under the Work Health and Safety Act 2011 and Work Health and Safety (Mines and Petroleum Sites) Act 2013.

The full report, including photographic evidence, contributing factors, and risk control guidance, is available via the NSW Resources Regulator website at resources.nsw.gov.au.