EO gas leakage in Ethylene Oxide sterilizers: dangerous warning signs that require immediate inspection

What is EO gas leakage?

EO gas leakage occurs when Ethylene Oxide gas escapes outside the controlled area instead of being contained inside the sterilization chamber, piping, valves, gas supply system, or exhaust system.

This issue may occur during different stages:

• When the machine starts vacuuming.
• When EO gas is supplied into the sterilization chamber.
• During the gas holding period for sterilization.
• When gas is discharged after the cycle.
• When the chamber door is opened after the cycle ends.
• When the aeration or ventilation system does not work effectively.

Signs that an EO sterilizer may be leaking gas

Businesses should pay attention if the machine shows one or more of the following signs. These symptoms should not be ignored, especially when the machine has been in operation for a long time or has recently developed issues after maintenance, parts replacement, or relocation.

When the machine cannot maintain vacuum, common symptoms include:

• Longer vacuuming time.
• The machine reports a vacuum leak error.
• The cycle stops midway.
• Abnormal pressure drop.
• The machine does not allow the cycle to start.

5. Unstable sterilization results

EO gas leakage is not only a safety issue, but also directly affects sterilization quality. If the gas is not maintained at the required concentration and contact time, products may fail to meet requirements even though the machine completes the full cycle.

Common locations that cause EO gas leakage

Based on practical inspection and maintenance of gas sterilizers, gas leakage is often related to the following areas:

Sterilization chamber door gasket

The door gasket is a component that can easily deteriorate after long-term operation. A hardened, deformed, cracked, dirty, or misaligned gasket can prevent the chamber door from sealing properly.

Door lock assembly and door pressing mechanism

If the door lock, hinge, or door pressing mechanism is misaligned, the chamber door may appear closed but still fail to achieve the required sealing level. This issue is often overlooked because the door may look properly closed from the outside.

EO gas supply valve

A stuck, worn, improperly closed, or incorrectly controlled gas supply valve can cause leakage during the gas injection stage or after the cycle has ended.

Piping, elbows, and gas connectors

Pipe joints, fittings, check valves, and cartridge/gas cylinder connectors are points that require periodic inspection. Small leaks in these areas may not cause immediate machine errors but still present significant risks.

Gas exhaust and ventilation system

An EO sterilizer does not only need a sealed chamber; it also needs a properly functioning gas exhaust and treatment system. If the exhaust fan is weak, the exhaust pipe is clogged, the exhaust valve fails, or the waste gas treatment system is ineffective, EO gas may remain in the chamber or spread into the working area.

EO gas sensors and monitoring system

Miscalibrated sensors, expired calibration, or improper sensor placement can cause inaccurate alarms. This is dangerous because operators may assume the area is safe while EO gas is still present.

Why should the machine not continue operating when EO gas leakage is suspected?

A small gas leak at the beginning can develop into a serious incident if the machine continues to run multiple cycles. In addition to health risks for operators, gas leakage also reduces the reliability of the sterilization process.

When the machine can no longer ensure proper sealing, parameters such as EO concentration, pressure, contact time, and gas exhaust efficiency may all be affected. This exposes businesses to risks related to product quality, operation records, and factory safety.

How does VietSonic inspect and handle EO gas leakage?

VietSonic provides inspection, repair, and maintenance services for EO gas sterilizers for factories, production workshops, medical units, cleanrooms, and businesses using gas sterilization systems.

Depending on the actual condition of the machine, technicians will inspect the main items below:

After inspection, VietSonic will identify the cause of the gas leak and recommend a suitable solution: replacing the gasket, aligning the door, repairing valves, fixing piping issues, inspecting the vacuum pump, calibrating sensors, or maintaining the gas exhaust system according to the actual condition of the equipment.

When should businesses call a technician to inspect an EO sterilizer?

Businesses should request an inspection if they encounter the following cases:

• The machine reports gas leak, pressure, or vacuum errors.
• There is an unusual chemical odor around the machine.
• Personnel feel uncomfortable when standing near the machine after a cycle.
• The machine takes too long to create vacuum.
• The sterilization cycle frequently stops midway.
• Biological indicator/chemical indicator results are unstable.
• The machine has been operating for a long time without periodic maintenance.
• Door gaskets, valves, or piping show signs of deterioration.
• The gas exhaust or aeration system operates weakly.