- Where Mixed Gas Diving Supervisor Jobs Actually Sit
- Who Hires Mixed Gas Diving Supervisors
- What the Job Involves Day to Day
- The Qualification Gate Employers Check First
- The Supervisor Card and Online Exam
- How the Five Exam Domains Map to Job Skills
- What Employers Look For Beyond the Card
- Building the Path From Diver to Supervisor
- A Domain-Ordered Prep Sequence
- Frequently Asked Questions
- This guide covers the ADCI HeO2/mixed-gas supervisor credential: card category, supervisor duties in Consensus Standards section 3.6, and the five study...
- Employers expect at least 350 field days, 150 working dives, and 30 working days as assistant mixed-gas supervisor.
- Air-diving supervisor qualification, written employer assignment, medical fitness, and valid CPR/first aid are all required alongside the exam.
- The issuer's certification page lists the supervisor card category at $275; question count, time limit, and passing score are not published.
Where Mixed Gas Diving Supervisor Jobs Actually Sit
Mixed gas diving supervisor jobs sit at the top of the surface-supplied diving workflow. The supervisor is the person with immediate control of the dive: the one who confirms the plan, watches the clock and gas, tends the diver, and decides when an operation stops. In the ADCI framework, that responsibility is spelled out in section 3.6 of the International Consensus Standards, and employers hire against it.
If you are new to the credential itself, start with What Is A Mixed Gas Diving Supervisor? and Mixed Gas Diving Supervisor Certification for the foundation. This article focuses on the other side of the equation: where the work is, who pays for it, and what a hiring manager expects you to bring.
Who Hires Mixed Gas Diving Supervisors
Mixed-gas supervisors work for commercial diving contractors that perform deeper surface-supplied operations using helium-oxygen breathing mixtures. The supervisor card is tied to a mode of diving, and the standards require employer vetting and a written assignment, so the employer relationship is part of the credential itself rather than an afterthought.
Typical employer categories include:
- Commercial diving contractors performing inspection, repair, and construction work at depth on marine structures.
- Offshore and subsea service companies that deploy surface-supplied mixed-gas spreads from vessels or platforms.
- Inland and nearshore marine construction firms whose scopes occasionally exceed air-diving practicality.
- Diving contractors that are ADCI members and align their operations manuals with the Consensus Standards.
Because the standards require supervisors to coordinate with vessels and work sites, you will also deal with clients, vessel masters, and site safety personnel as part of the role. Hiring managers value supervisors who can communicate across those groups under pressure.
What the Job Involves Day to Day
Section 3.6 reads like a job description, and it is worth reading as one. The responsibilities listed there translate directly into the daily rhythm of a mixed-gas supervisor job.
Before the dive
- Verify compliance with regulations and the employer's operations manual.
- Confirm that life-support equipment is suitable, compliant, and inspected.
- Choose a suitable surface location for supervisory control.
- Complete job safety analysis and dive planning, including gas supplies.
- Confirm team duties and the fitness of each team member.
- Ensure current manuals, decompression tables, and treatment information are on hand.
- Hold a team briefing covering operation-specific procedures.
- Perform pre-dive checks.
During the dive
- Maintain immediate supervisory control at all times.
- Track depth, time, and gas profiles against the plan.
- Keep the diver continuously tended.
- Maintain emergency and medical communications.
- Apply termination criteria when conditions or diver status demand it.
After the dive
- Perform post-dive checks and observe the diver for symptoms.
- Confirm chamber availability and post-treatment arrangements.
- Complete incident reports and maintenance records, and verify logs.
Key Takeaway
The exam and the job use the same source. If you can walk through section 3.6 from planning to log verification and explain the reason behind each duty, you are preparing for the credential and for the work simultaneously.
The Qualification Gate Employers Check First
Before a company puts you in a mixed-gas supervisor chair, the standards require a stack of prerequisites. Hiring managers screen against these before they ever discuss pay or schedules. For a deeper walkthrough, see Mixed Gas Diving Supervisor Requirements.
| Requirement | What it means for job seekers |
|---|---|
| Passing the ADCI HeO2/mixed-gas supervisor examination | The credentialing test itself; delivered online per the issuer's certification page. |
| At least 350 field days as air or mixed-gas diver | Documented time in the water; logbooks matter. |
| 150 working dives | Counts working dives specifically, not just days on a vessel. |
| 30 working days as assistant mixed-gas supervisor | Supervised experience in the role before taking it over. |
| Qualification as air-diving supervisor | The air supervisor foundation comes first. |
| Employer vetting and written assignment | You need an employer willing to put the assignment in writing. |
| Mode-specific supervisor card | The card is tied to mixed-gas mode, not a general supervisor card. |
| Medical fitness before hyperbaric exposure | Current fitness documentation is non-negotiable. |
| Valid CPR and first aid | Must stay current to hold the role. |
The 30 working days as assistant mixed-gas supervisor is the step candidates most often underestimate. It requires a current employer willing to give you assistant time on mixed-gas jobs, which means your career moves in the years before the exam matter. Plan your employer choices with that bottleneck in mind.
The Supervisor Card and Online Exam
The issuer's current certification page lists an online exam as required and shows $275 for the supervisor card category. That is the figure to anchor on when budgeting, but treat it carefully: it is the card category fee as listed by the issuer, not an independently verified exam-only price. Confirm the current amount and what it covers directly with ADCI before paying. For a wider budget view, see Mixed Gas Diving Supervisor Certification Cost.
Several details are simply not established in public sources: the question count, the time limit, the passing score, the pass rate, and any official domain weighting. Be skeptical of any site that quotes precise figures for those. If you want context on how to think about that uncertainty, read Mixed Gas Diving Supervisor Passing Score and Mixed Gas Diving Supervisor Pass Rate.
How the Five Exam Domains Map to Job Skills
The five study groupings used on this site are an editorial map of the published ADCI sections, not an official weighted blueprint. They are still the most practical way to connect preparation to job performance. The full breakdown lives in Mixed Gas Diving Supervisor Exam Domains; here is how each one shows up in the work.
Domain 1: HeO2/Mixed-Gas Diving Supervisor responsibilities, qualifications and certification
This is section 3.6 territory and the backbone of the job. Employers expect you to know your duties cold.
- Regulatory and employer-manual compliance
- Qualification, card, and assignment requirements
- Team fitness, briefings, and operation-specific procedures
- Incident reports, maintenance records, and log verification
Domain 2: Surface-Supplied Mixed-Gas Diving (HeO2)
Section 4.4 covers operational personnel and equipment requirements for surface-supplied mixed-gas work. This is where the mode-specific nature of the card becomes concrete.
- Personnel and equipment requirements for the mode
- Gas supply planning and depth/time/gas profiles
- Apply mixed-gas context, not saturation-specific provisions as universal rules
Domain 3: Underwater Operations: Procedures, Checklists and Guidelines
Drawn from the operations sections, this domain is about running the dive: checklists, tending, and termination decisions.
- Pre-dive and post-dive checks
- Continuous tending and communications
- Termination criteria and post-dive observation
Domain 4: Life-Support Equipment: Requirements, Maintenance and Testing
Supervisors answer for the gear. The equipment sections cover a wide list a hiring manager will expect you to speak about fluently.
- Dress and emergency gas, helmets and masks
- Hoses and umbilicals, manifolds and regulators
- Compressors and air purity, gauges and timekeeping
- Launch and recovery, entry and egress
- Compressed-gas equipment and pressure vessels for human occupancy
- Maintenance and testing requirements
Domain 5: Emergency Procedures, Assessments and Reporting of Accidents
This is where supervisors earn their pay. Interviews often probe how you would respond to a loss of breathing media or a trapped diver.
- Loss of breathing media or communications
- Trapped or injured diver, umbilical damage
- Fire, equipment failure, and adverse conditions
- Chamber availability, medical communications, and accident reporting
What Employers Look For Beyond the Card
The card opens the door; the rest of your profile decides whether you walk through it. Based on what the standards demand of the role, these are the signals that matter.
- A clean, verifiable logbook. The 350 field days, 150 working dives, and 30 assistant-supervisor days all need documentation. Gaps and vague entries slow vetting.
- Planning discipline. Job safety analysis and gas-supply planning are written into section 3.6. Supervisors who can show organized dive plans stand out.
- Calm communication. Emergency and medical communications are a named duty. Employers listen for how you describe stressful events.
- Equipment literacy. You do not repair every component, but you must judge suitability, compliance, and inspection status quickly.
- Records habits. Incident reports, maintenance records, and log verification are supervisor responsibilities, and sloppy paperwork is a red flag.
- Fitness and currency. Medical fitness and valid CPR/first aid must be current, so keep them from lapsing between contracts.
Building the Path From Diver to Supervisor
The route to a mixed-gas supervisor job is sequential, and each step depends on the one before it.
- Build field days. Work toward 350 field days as an air or mixed-gas diver, logging each carefully.
- Accumulate working dives. Reach 150 working dives, which are distinct from simply being on a diving job.
- Qualify as an air-diving supervisor. This is a required foundation, not an optional step.
- Secure assistant supervisor time. Find an employer who will give you 30 working days as assistant mixed-gas supervisor.
- Get vetted and assigned in writing. Your employer must formally assign you to the role.
- Pass the exam and obtain the card. Complete the online ADCI HeO2/mixed-gas supervisor examination and pay the card category fee.
- Maintain currency. Keep medical fitness and CPR/first aid valid throughout.
For a candid look at how demanding the testing step is relative to the experience steps, see How Hard Is the Mixed Gas Diving Supervisor Exam? Most candidates find the experience requirements, not the exam, to be the longer part of the journey.
A Domain-Ordered Prep Sequence
Because the exam draws on specific ADCI sections, the order in which you study should follow the structure of the standards rather than a generic calendar. This is one workable sequence that mirrors how a supervisor thinks through a dive.
Domain 1 first
- Read section 3.6 end to end and restate each duty in your own words.
- Memorize the qualification and card prerequisites.
Domain 2 and Domain 3
- Work through section 4.4 and the operations sections together.
- Practice walking through depth/time/gas profiles and termination criteria.
Domain 4
- Review the equipment sections: dress, helmets, umbilicals, compressors, manifolds, gauges, launch and recovery, pressure vessels for human occupancy.
- Focus on maintenance and testing requirements.
Domain 5 and full review
- Drill emergency scenarios: media loss, trapped diver, umbilical damage, fire.
- Take timed practice questions across all five domains.
Start with Domain 1 because every other domain assumes you understand the supervisor's authority and obligations. Save emergencies for last so you can apply everything else to them. For a fuller plan, use the Mixed Gas Diving Supervisor Study Guide, keep the Mixed Gas Diving Supervisor Cheat Sheet nearby for quick review, and test yourself with the Mixed Gas Diving Supervisor practice tests. If you want structured coursework context, see Mixed Gas Diving Supervisor Training.
Key Takeaway
Do not treat saturation-specific provisions as universal mixed-gas requirements. The exam applies mixed-gas context, so keep your focus on surface-supplied HeO2 operations when you study the standards.
Frequently Asked Questions
The Association of Diving Contractors International (ADCI) administers the HeO2/mixed-gas supervisor examination and card, using its International Consensus Standards as the source material. This is distinct from ADC-UK or IMCA schemes.
The standards call for at least 350 field days as an air or mixed-gas diver, 150 working dives, and 30 working days as assistant mixed-gas supervisor, along with air-diving supervisor qualification, employer vetting and written assignment, medical fitness, and valid CPR/first aid.
The issuer's certification page currently lists $275 for the supervisor card category and indicates an online exam is required. That should not be read as an independently verified exam-only fee, so confirm current pricing with ADCI before you pay.
Public sources do not establish the question count, time limit, passing score, or pass rate, and there is no official domain weighting table. Be wary of any source that quotes exact numbers for those details.
The focus is surface-supplied mixed-gas (HeO2) diving. Saturation-specific provisions should not be treated as universal mixed-gas examination requirements, so study the standards with the mixed-gas context in mind.
Mixed gas diving supervisor jobs reward people who combine documented experience with disciplined planning and calm emergency judgment. Build your logbook, line up the assistant-supervisor time, and prepare by domain against the ADCI standards. When you are ready to test yourself, head to the main practice test site, and revisit the certification overview as you plan your next career move.