A federal enforcement case involving two fatal releases from industrial kettles offers important lessons for laboratories operating autoclaves, reactors, pressure vessels, and other equipment that combine heat and pressure.
The US Occupational Safety and Health Administration (OSHA) recently announced that it had cited Wisconsin food manufacturer NaturPak after two incidents killed three workers and seriously injured two others. The incidents did not occur in a laboratory, but the underlying hazards are relevant wherever personnel work near equipment capable of retaining pressure.
Pressure can remain when flow is blocked
According to OSHA, the first incident occurred after a kettle’s vent line clogged, allowing pressure to build up. The lid unexpectedly opened, releasing steam, hot liquid, and organic material onto two employees. One employee later died from the injuries.
A second kettle incident occurred approximately one month later. A lid opened while the vessel was under pressure, releasing hot material and steam. Two workers died, and another required hospitalization.
OSHA cited the company for pressure and thermal hazards associated with kettle design and use. The agency also issued citations related to fall exposure and notification of employees working near permit-required confined spaces. OSHA notes that citations and penalties can change as a case proceeds.
For laboratories, the case highlights why operators should never rely on routine appearance or familiarity as evidence that pressurized equipment is safe to open. Autoclaves and similar systems require functioning vents, pressure-relief devices, door interlocks, seals, gauges, and controls. A blocked line or failed component can change the equipment’s risk profile before staff sees an obvious warning.
Maintenance and operating procedures work together
Preventive maintenance schedules should follow manufacturer requirements and account for equipment age, workload, materials processed, and prior failures. Managers should document inspections, repairs, and recurring alarms, then investigate patterns rather than repeatedly returning equipment to service without identifying the cause.
Operating procedures should address normal cycles, blocked vents, abnormal pressure readings, failed interlocks, leaks, incomplete depressurization, and power interruptions. Staff need clear stop-work criteria and a defined process for isolating equipment and contacting qualified service personnel.
Training should make stored-energy hazards visible. Before opening equipment, personnel must confirm that pressure has returned to a safe level and follow the manufacturer’s instructions for cooling, venting, and unloading. Appropriate PPE can reduce exposure, but it does not replace engineering controls or safe equipment design.
The OSHA case also reinforces the importance of learning after a near miss or injury. Laboratory leaders should treat abnormal releases, repeated clogs, unexpected lid movement, and recurring pressure alarms as signals requiring investigation. Prompt corrective action can keep a known equipment problem from becoming a repeated exposure.
This article was created with the assistance of Generative AI and has undergone editorial review before publishing.
