Marine Concrete AHA (Activity Hazard Analysis / Job Hazard Analysis)

Updated 2026-06-23

A Marine Concrete AHA (Activity Hazard Analysis / Job Hazard Analysis) is the plan that keeps the crew placing marine concrete safe from drowning and water work, through the over-water and marine access and formwork, and around the tidal currents and placement timing. Marine concrete constructs concrete in, over, and around water — combining the drowning and water-work hazard, the over-water and marine-access/formwork hazard, and the tidal- current and placement-timing hazard. This guide walks through building a Marine Concrete AHA that names the drowning/water-work, over-water/marine-access-formwork, and tidal-current/placement-timing hazards and assigns the drowning, marine-access, and tidal controls that hold up in the field.

Why marine concrete needs its own AHA

Marine concrete is concrete construction in a marine or water environment — piers, docks, wharves, seawalls, bridge piers, marine foundations, and other concrete placed in, over, or adjacent to water, often involving underwater placement, cofferdams, or work from barges and over-water platforms. The defining feature is the water environment: the drowning hazard dominates, the access is over water (from barges, platforms, cofferdams), and the tides and currents affect the work and the concrete placement. The hazards combine the drowning and water-work (working in, over, and around water — the drowning hazard (the dominant marine hazard — falls into water, working over water, working from vessels/barges)), the over-water and marine-access/formwork (the access is over water and the formwork is in/over water (barges, over-water platforms, cofferdams, marine formwork) — the marine- access, over-water-work, and marine-formwork hazards), the tidal-current and placement-timing (tides and currents affect the work and the concrete placement (underwater/tidal-zone placement must be timed and protected — tidal windows, current, water in the pour)), and the wet-concrete/marine-conditions. The drowning/water-work and the over-water/marine-access-formwork justify a dedicated AHA.

Breaking marine concrete into steps

The steps for a Marine Concrete AHA follow the marine work:

• Establish the drowning-prevention program (PFDs, water rescue)
• Set up the marine access (barges, platforms, cofferdams)
• Erect the marine formwork (in/over water)
• Time the placement to the tides/currents
• Place the concrete (underwater/tidal-zone methods)
• Manage the drowning, access, and tidal hazards
• Cure and protect from water/tidal action
• Complete

Each step carries a hazard, and the drowning/water-work, the over-water/marine-access-formwork, and the tidal- current/placement-timing are where the most significant risks concentrate.

The hazards step by step

Drowning and water-work

Working in, over, and around water — the drowning hazard (the dominant marine hazard — falls into water, working over water, working from vessels/barges). The controls are the drowning-prevention program (personal flotation devices (PFDs) for work over/near water, guardrails/fall protection at water edges, ring buoys and water-rescue capability, a rescue skiff/boat where required), no lone work over water, and the drowning controls. The drowning/water-work is the primary defining hazard — drowning is the dominant marine hazard. (These follow the working-over-water fundamentals.)

Over-water and marine-access/formwork

The access is over water and the formwork is in/over water (barges, over-water platforms, cofferdams, marine formwork) — the marine-access, over-water-work, and marine-formwork hazards. The controls are safe marine access (barges, over-water platforms/staging, cofferdams — stable, guarded), safe over-water work (fall protection, PFD), marine formwork appropriate to the water/tidal loads (formwork in/over water must resist water and tidal forces), and the marine-access/formwork controls. The over-water/marine-access-formwork is a defining hazard — the access and formwork are over/in water. (These follow the marine-construction fundamentals.)

Tidal-current and placement-timing

Tides and currents affect the work and the concrete placement (underwater/tidal-zone placement must be timed and protected — tidal windows, current, water in the pour). The controls are timing the work/placement to the tides (working and placing in the tidal windows, awareness of the tide schedule and currents), protecting the placement from water (cofferdams/forms keeping water out of the pour, or proper underwater-placement methods like tremie where placing underwater), current awareness (currents affect vessels, workers in water, and the work), and the tidal/timing controls. The tidal-current/placement-timing is a defining hazard — tides and currents govern marine placement. (These follow the tidal-work fundamentals.)

Wet-concrete/marine-conditions

The wet concrete and marine conditions (caustic wet concrete, weather/marine exposure) carries the contact/ exposure hazard. The controls are wet-concrete contact protection, weather/marine-exposure management, and the contact/conditions controls. (These follow the cement-contact fundamentals.)

A simple Marine Concrete AHA structure

Drowning prevention and marine-access/tidal management

A Marine Concrete AHA centers on drowning prevention and marine-access/tidal management. The drowning prevention addresses the dominant water hazard — controlled by the drowning-prevention program (PFDs for work over/near water, guardrails/fall protection at water edges, ring buoys and water-rescue capability, a rescue boat where required) and no lone work over water. The marine-access/tidal management addresses the over-water access, formwork, and tides — controlled by safe marine access (barges, platforms, cofferdams) and formwork resisting water/tidal loads, and timing the work and placement to the tides and currents with the placement protected from water. And the wet concrete and marine conditions get contact and exposure controls. An AHA built on drowning prevention and marine-access/tidal management, with contact controls, addresses the hazards that define marine concrete.

From the field: what actually goes wrong

In fourteen years across federal, heavy civil, and industrial projects, marine concrete constructs concrete in, over, and around water, and the water environment redefines the hazard profile — the concrete work is familiar, but it is all happening in a place where a fall means going into the water. The drowning and water-work hazard is the primary defining concern — marine concrete work is done in, over, and around water (from barges, over-water platforms, cofferdams, and at the water's edge), so the drowning hazard is dominant and ever-present: a worker who falls from a barge, platform, or the edge, or who is working over water, faces drowning. So the drowning-prevention program is the foundation: personal flotation devices (PFDs) for work over and near water, guardrails and fall protection at water edges, ring buoys and water-rescue capability positioned and ready, a rescue skiff or boat where required, and no lone work over water. Drowning prevention is the marine-specific control that underlies everything else, because the water is always there.

The over-water/marine-access-formwork and the tidal-current/placement-timing are the other defining hazards. On the projects I have run, the access and the formwork are over and in the water — workers reach the work from barges, over-water platforms and staging, and cofferdams, and the formwork itself is built in or over the water (marine formwork that has to resist water and tidal forces) — so safe marine access (stable, guarded barges and platforms, properly built cofferdams), safe over-water work (fall protection and PFDs together), and marine formwork appropriate to the water and tidal loads are the controls. And the tidal-current/placement-timing hazard is genuinely distinctive to marine work: tides and currents govern the work, because concrete placement in the tidal zone or underwater must be timed to the tidal windows and protected from the water (a pour cannot simply be washed by an incoming tide or diluted by water in the forms), so timing the work and placement to the tides, protecting the placement from water (cofferdams and forms keeping water out of the pour, or proper underwater-placement methods like tremie concrete where placing underwater), and current awareness (currents affect vessels, workers, and the work) are the controls. The tides and currents dictate when and how marine concrete can be placed. The wet-concrete contact and marine-exposure hazards round it out. The AHA built on drowning prevention and marine-access/tidal management is the one that protects the marine-concrete crew.

The bottom line

A Marine Concrete AHA names the drowning/water-work, the over-water/marine-access-formwork, and the tidal-current/ placement-timing hazards with specific controls — a drowning-prevention program (PFDs, water rescue, edge protection) for the dominant water hazard, safe marine access and formwork resisting water/tidal loads, and timing the placement to the tides with the pour protected from water. The drowning prevention and the marine-access/tidal management are the defining concerns. The AHA that manages both is the one that protects the crew.

Frequently asked questions

Why is drowning the dominant marine-concrete hazard?

Marine concrete work is done in, over, and around water (from barges, over-water platforms, cofferdams, and at the water's edge), so the drowning hazard is dominant and ever-present — a worker who falls from a barge, platform, or edge, or who is working over water, faces drowning. Controls are the drowning-prevention program (PFDs for work over/near water, guardrails/fall protection at water edges, ring buoys and water-rescue capability, a rescue skiff/boat where required), no lone work over water, and the drowning controls.

What marine-access and formwork hazards apply?

The access and formwork are over and in the water — workers reach the work from barges, over-water platforms, and cofferdams, and the formwork is built in or over the water and must resist water and tidal forces. Controls are safe marine access (barges, over-water platforms/staging, cofferdams — stable, guarded), safe over-water work (fall protection, PFD), marine formwork appropriate to the water/tidal loads, and the marine-access/formwork controls.

How do tides and currents affect marine concrete placement?

Tides and currents govern the work, because concrete placement in the tidal zone or underwater must be timed to the tidal windows and protected from the water (a pour cannot be washed by an incoming tide or diluted by water in the forms). Controls are timing the work/placement to the tides (working/placing in the tidal windows, awareness of the tide schedule and currents), protecting the placement from water (cofferdams/forms keeping water out, or underwater-placement methods like tremie), current awareness, and the tidal/timing controls.

What is marine concrete?

Marine concrete is concrete construction in a marine or water environment — piers, docks, wharves, seawalls, bridge piers, marine foundations, and other concrete placed in, over, or adjacent to water, often involving underwater placement, cofferdams, or work from barges. Because the drowning hazard dominates, the access and formwork are over/in water, and tides and currents govern the placement, those hazards apply.

Related AHAs and JHAs

• Structural Concrete AHA — the structural concrete fundamentals
• Cast-in-Place Concrete AHA — the cast-in-place concrete fundamentals
• Pile Driving Operations JHA — related marine/foundation work
• Sheet Pile Installation JHA — related cofferdam/marine work

Written by Mustafa Tok, CSP, ASP, CHST — OSHA Authorized Outreach Trainer with 14+ years of international construction safety experience across federal, heavy civil, and industrial projects.