Halcyon Dive Systems has launched a mandatory safety inspection and service campaign affecting all oxygen Manual Add Valve (MAV) regulators used with its Symbios closed-circuit rebreather (CCR), following reports of oxygen-fire events involving the assemblies.
The company is advising Symbios owners to stop using affected equipment until the inspection and service process has been completed.
In a safety notice issued this week, Halcyon said it had received reports of oxygen-fire incidents involving oxygen-service MAV regulator assemblies used with the Symbios rebreather system. The company subsequently determined that some regulators may contain particles or manufacturing residue that could increase the risk of oxygen ignition.
“Additional inspection and service measures related to the MAV regulator assembly are required to further enhance safety and ensure continued compliance with Halcyon’s oxygen-service standards,” the company said.
Free Inspection and Service Program
Under the campaign, affected regulators will be inspected and serviced at no cost through authorized Halcyon service centers.
According to the manufacturer, technicians will:
- Verify oxygen-service cleanliness standards
- Perform any required cleaning or corrective maintenance
- Install a flow restrictor in the oxygen pressure-sensor supply circuit where required
- Confirm proper assembly and operational performance before returning units to service
Halcyon noted that the regulator design had previously passed oxygen-compatibility testing. The additional flow restrictor is being installed to provide an extra margin of safety and reduce the potential consequences of an oxygen-system ignition event.
Focus on Oxygen Cleanliness
The issue highlights one of the most critical aspects of rebreather maintenance: oxygen cleanliness.
The Symbios owner’s manual contains extensive warnings regarding oxygen contamination risks, noting that particles, dust, grease, hydrocarbons, or improper servicing can create ignition sources in high-pressure oxygen systems. The manual also specifies that oxygen-service components must remain oxygen-clean and that only approved oxygen-compatible materials should be used.
While Halcyon has not disclosed how many incidents have occurred, whether any injuries were reported, or how many units may be affected, the company has stated that enhanced manufacturing controls have already been implemented.
Manufacturing Changes Introduced
In response to the issue, Halcyon says it has strengthened inspection, assembly, cleaning, and quality-verification procedures. The company has also moved to in-house cleaning and assembly processes alongside 100 percent inspection of MAV regulators used in current and future production.
A New Rebreather Platform
The Symbios CCR is one of the industry’s newest closed-circuit rebreather platforms. Following a limited release program involving instructors, explorers, and early adopters, the system entered wider global availability earlier this year. The unit features a chest-mounted design, wireless communications architecture, integrated bailout systems, and hybrid oxygen-sensing technology.
Halcyon has advised all Symbios owners to contact their nearest authorized service center for inspection and servicing before further use.
The company has not announced a product recall and is instead describing the action as a mandatory safety inspection and service campaign.
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