Pre-dive safety procedures

The employer must keep at the dive location an accessible list with phone or call numbers for an operational decompression chamber (if not at the dive location), accessible hospitals, available physicians, available means of transportation, and the nearest U.S. Coast Guard Rescue Coordination Center. See the emergency-aid requirements in 1910.421(b) and the specific items listed in 1910.421(b)(1)–(5).

• Keep the list where the dive team can reach it quickly (surface control, dive boat, or shore station).
• Update telephone numbers and locations before operations that change area or support resources.
• If the decompression chamber is offsite, include its operational status and directions as required by 1910.421(b)(1).

If there is no decompression chamber at the dive location, the employer must keep at the dive location the telephone or call number of an operational decompression chamber that can be reached to support the dive operation. This is required by 1910.421(b)(1).

• Verify the chamber is operational and reachable before diving.
• Include directions and estimated travel time to the chamber so that rescue/transport decisions can be made quickly.
• Coordinate emergency procedures with the chamber’s staff as part of your planning under 1910.421(d)(9).

The employer must have a first aid kit at the dive location that is appropriate for the diving operation and approved by a physician. This is required by 1910.421(c)(1).

• "Appropriate for the diving operation" means the kit should contain supplies relevant to diving injuries (e.g., cuts, immersion-related injuries, initial care for decompression illness) and be sized for the number of personnel.
• Having a physician approve the kit ensures medical suitability and that the supplies match local treatment protocols and the diving profile.
• Replenish and inspect the kit before each dive to ensure readiness as part of pre-dive checks under 1910.421(g).

First aid kits that are used inside decompression chambers or bells must be suitable for use under hyperbaric conditions. This requirement is stated in 1910.421(c)(2).

• "Suitable for use under hyperbaric conditions" means items must function safely and effectively at elevated pressure (e.g., packaging that won’t rupture, tools that won’t cause sparks, medications stored appropriately).
• Confirm with a physician and hyperbaric specialists what specific supplies and packaging are acceptable for chamber use as part of your kit approval in 1910.421(c)(1).

In addition to a physician-approved first aid kit, the employer must have an American Red Cross standard first aid handbook (or equivalent) and a bag-type manual resuscitator with transparent mask and tubing available at the dive location, as required by 1910.421(c)(3).

• The first aid handbook provides standardized guidance for initial care and should be accessible to the dive team.
• A bag-type manual resuscitator (BVM) with transparent mask and tubing is essential for airway management and ventilation support until advanced medical care arrives or transfer to a hyperbaric chamber is possible.
• Make sure the BVM and masks are inspected, clean, and suitable for any hyperbaric use if they will be taken into a chamber (see 1910.421(c)(2)).

The employer must assess diving mode; surface and underwater conditions and hazards; breathing gas supply (including reserves); thermal protection; diving equipment and systems; dive team assignments and fitness (including known impairments); repetitive dive designation or residual inert gas status; decompression and treatment procedures (including altitude corrections); and emergency procedures. These required planning items are listed in 1910.421(d)(1)–(9).

• Document assessments for each dive so that decisions (e.g., gas reserves, thermal suits, contingency plans) are clear to the dive team.
• Use the assessment to inform briefings under 1910.421(f).
• Re-assess when conditions change (weather, visibility, currents) and adjust plans accordingly as part of the employer’s duty under 1910.421(a).

Employers must assess the breathing gas supply for the dive operation, including reserves sufficient to handle contingencies, as required by 1910.421(d)(3).

• Calculate consumption rates for planned depths and durations, and include reserves for unexpected delays, buddy-assistance, or emergencies.
• Ensure gas compatibility with equipment, check fill quality, and inspect delivery systems during the pre-dive equipment inspection under 1910.421(g).
• Document the reserve policy and make it known in the dive briefing per 1910.421(f)(1)(ii).

Before assigning dive team members, the employer must assess dive team assignments and the physical fitness of team members, including any impairment known to the employer, as required by 1910.421(d)(6).

• Ask each diver about their current state of physical fitness before assignment as required by the briefing rules in 1910.421(f)(2).
• Consider recent illnesses, medication use, fatigue, alcohol, or conditions that affect fitness to dive and document any limitations.
• Ensure team members know how to report physical problems or adverse effects during and after the dive per 1910.421(f)(2).

Employers must assess whether a dive is part of repetitive diving and the residual inert gas status of dive team members so decompression planning and safety margins account for prior nitrogen loading, as required by 1910.421(d)(7).

• Record prior dive profiles, surface intervals, and remaining inert gas loads to determine safe repetitive dive limits.
• Use recognized decompression tables or dive computer algorithms that account for residual inert gas when planning subsequent dives.
• Include this information in briefings and decompression procedures under 1910.421(f)(1)(iii) and 1910.421(d)(8).

Employers must include decompression and treatment procedures in dive planning and must account for altitude corrections when appropriate, per 1910.421(d)(8).

• Establish decompression schedules, emergency oxygen administration, and in-water or chamber treatment plans.
• Adjust profiles and tables/computer settings for dives at altitude or when surface elevation affects decompression requirements.
• Make these procedures part of the pre-dive briefing in 1910.421(f)(1)(ii)–(iv).

Emergency procedures must be part of the dive planning assessment and should be sufficiently detailed to address foreseeable incidents, including rapid access to medical care, decompression chamber activation, rescue and evacuation routes, and communication plans, as required by 1910.421(d)(9).

• Include contact numbers required by 1910.421(b).
• Practice emergency drills and include roles for each team member so response is immediate and coordinated.
• Ensure transport means and hospital coordination are confirmed before diving (see 1910.421(b)(2)–(4)).

Employers must coordinate diving operations with other activities in the vicinity that are likely to interfere with the dive team, to minimize hazards to the dive team, consistent with 1910.421(e).

• Identify nearby vessel traffic, construction, dredging, or air operations that could create hazards (prop wash, lines, noise, suspension of work).
• Communicate schedules and exclusion zones to other operators; use signaling and surface control measures to prevent interference.
• If coordination isn’t possible, postpone the dive or add controls (lookouts, barriers, NOTAMs) as part of the planning assessment in 1910.421(d).

Before a dive, dive team members must be briefed on the tasks to be undertaken; safety procedures for the diving mode; any unusual hazards or environmental conditions likely to affect safety; and any modifications to operating procedures necessitated by the specific diving operation, as required by 1910.421(f)(1)(i)–(iv).

• Make the briefing interactive so divers can ask questions and confirm understanding.
• Cover emergency procedures, gas reserve limits, hand signals, communications, and surface support roles.
• Document the briefing topics and any special instructions or procedural changes to ensure consistency with 1910.421(f)(1).

Prior to assigning individual dive team members, the employer must inquire into each diver's current state of physical fitness and must tell them how to report physical problems or adverse physiological effects during and after the dive, as required by 1910.421(f)(2).

• Ask about recent illness, medication, recent dives, fatigue, alcohol use, or any symptoms that could affect diving safety.
• Make reporting procedures clear (who to tell, how to communicate in-water or on surface) and ensure confidentiality and non-retaliation for reporting.
• Record the readiness checks where appropriate and act on any concerns before allowing the dive to proceed in line with 1910.421(d)(6).

The breathing gas supply system (including reserve breathing gas supplies), masks, helmets, thermal protection, and bell handling mechanism (when appropriate) must be inspected prior to each dive, as required by 1910.421(g).

• Check tanks, valves, hoses, regulators, fittings, and pressure readings; verify reserve gases and alarms.
• Inspect masks and helmets for seal integrity, communications, and fit; verify thermal protection for appropriate insulation and fit.
• For bell operations inspect handling mechanisms, umbilicals, and seals, and ensure maintenance records are current as part of pre-dive readiness in 1910.421(a).

When diving from surfaces other than vessels in areas capable of supporting marine traffic, a rigid replica of the international code flag "A" at least one meter in height must be displayed at the dive location with all-round visibility and must be illuminated during night operations, as required by 1910.421(h).

• The flag must be positioned so boaters and other watercraft can clearly see and recognize the dive area.
• Illuminate the flag during night dives to maintain visibility and reduce collision hazards in line with the standard’s intent.
• Use this marking along with other surface-control measures (lookouts, buoys) identified during planning in 1910.421(d).

The employer is responsible for complying with the pre-dive procedure requirements prior to each diving operation unless otherwise specified, as stated in 1910.421(a).

• This responsibility includes maintaining emergency contacts (1910.421(b)), providing appropriate first aid supplies (1910.421(c)), conducting planning/assessments (1910.421(d)), and ensuring briefings and equipment inspections (1910.421(f); 1910.421(g)).
• Employers should document procedures and training to demonstrate compliance during operations and inspections.

Employers must assess thermal protection as part of dive planning and provide protection appropriate for the water temperature and dive duration, as required by 1910.421(d)(4).

• Select drysuits, wetsuits, or heated systems based on environmental conditions, expected exposure, and physiological needs of divers.
• Inspect thermal-protection gear as part of the pre-dive equipment inspections in 1910.421(g).
• Include thermal protection considerations in the dive briefing so divers understand limitations and emergency procedures for hypothermia under 1910.421(f)(1)(iii).

Employers must assess diving equipment and systems for safety and reliability and inspect them prior to each dive, including breathing gas systems, masks, helmets, umbilicals, communications, and handling systems as required by 1910.421(d)(5) and 1910.421(g).

• Verify maintenance history, correct assembly, and functional testing (e.g., regulator checks, communications tests, valve operation).
• Confirm spare parts, redundancy (e.g., reserve gas, backup communications), and contingency plans for equipment failure.
• Document inspections and remedial actions before the dive to ensure continuous compliance with the pre-dive requirements in 1910.421(a).

When briefing for a specific diving mode, employers must cover safety procedures specific to that mode (surface-supplied, SCUBA, mixed gas, bell operations, etc.), including emergency responses, communications, and mode-specific equipment checks as required by 1910.421(f)(1)(ii).

• For surface-supplied operations, brief on umbilical management, tender responsibilities, and gas-loss contingencies.
• For SCUBA or mixed-gas dives, include gas-switching procedures, bailout plans, and decompression schedules.
• Make sure mode-specific hazards and modifications to procedures are recorded and understood per 1910.421(f)(1)(iv).

The employer must have the nearest U.S. Coast Guard Rescue Coordination Center phone number at the dive location to ensure rapid coordination of maritime search-and-rescue and specialized emergency resources when required, as specified in 1910.421(b)(5).

• The Coast Guard can provide rescue vessels, helicopters, and maritime coordination in incidents involving boats, divers lost at sea, or mass rescue situations.
• Include contact protocols and who on the dive team is authorized to make the call in your emergency procedures under 1910.421(d)(9).
• Keep updated regional Coast Guard contact information for the specific area of operations as part of pre-dive checks.

First aid kits must be maintained and available at the dive location as required by 1910.421(c), and breathing gas systems and related equipment must be inspected prior to each dive under 1910.421(g).

• Inspect and restock first aid kits after every use and check them before each diving operation to ensure physician-approved contents are present and within expiration dates (1910.421(c)(1)).
• Conduct pre-dive inspections of breathing gas supplies, reserves, masks, helmets, thermal gear, and bell handling mechanisms before every dive as required by 1910.421(g).
• Keep inspection checklists and records to demonstrate compliance and to identify trends that may require maintenance or training changes.