Bentonite Waterproofing AHA (Activity Hazard Analysis / Job Hazard Analysis)
Updated 2026-06-23
A Bentonite Waterproofing AHA (Activity Hazard Analysis / Job Hazard Analysis) is the plan that keeps the crew doing bentonite waterproofing safe from the below-grade excavation and confined space, from the bentonite dust and slip, and around the material handling and installation. Bentonite waterproofing applies bentonite-clay waterproofing — combining the below-grade-excavation and confined-space hazard, the bentonite-dust and slip hazard, and the material-handling and installation hazard. This guide walks through building a Bentonite Waterproofing AHA that names the below-grade-excavation/confined-space, bentonite-dust/slip, and material-handling/ installation hazards and assigns the excavation, dust, and handling controls that hold up in the field.
Why bentonite waterproofing needs its own AHA
Bentonite waterproofing is the application of bentonite-clay waterproofing — the sodium bentonite clay waterproofing (applied as loose/granular bentonite, bentonite-based coatings, or in panel/sheet forms) that swells when wet to form a waterproof barrier, applied to below-grade walls, foundations, and structures. This heads the bentonite waterproofing cluster (panel and composite-sheet forms follow). The defining feature is that bentonite is a clay-based system, so — unlike the solvent, bituminous, hot-applied, and reactive waterproofing — it has no solvent-vapor, hot-work, or isocyanate hazards; its hazards are the below-grade location (excavation/confined space), the bentonite dust (dry bentonite is a dust — a respiratory/eye irritant, and bentonite may contain some crystalline silica) and the slip hazard (wet bentonite is extremely slippery), and the material handling. The hazards combine the below-grade-excavation and confined-space (the below-grade location — the excavation and confined-space hazards), the bentonite-dust and slip (the dry bentonite dust and the wet-bentonite slip — the dust and slip hazards), the material-handling and installation (handling and installing the bentonite material — the handling hazard), and the eye. The below-grade-excavation/confined-space and the bentonite-dust/slip justify a dedicated AHA.
Breaking bentonite waterproofing into steps
The steps for a Bentonite Waterproofing AHA follow the work:
- Assess the location (excavation/confined space)
- Set up excavation/confined-space protections
- Prepare the surface
- Apply the bentonite waterproofing (dust control)
- Manage the below-grade, dust, and slip hazards
- Protect the bentonite from premature wetting
- Backfill or complete
- Complete
Each step carries a hazard, and the below-grade-excavation/confined-space, the bentonite-dust/slip, and the material-handling/installation are where the most significant risks concentrate.
The hazards step by step
Below-grade-excavation and confined-space
The below-grade location — the excavation and confined-space hazards. The controls are excavation and confined-space protections (bentonite waterproofing is applied against below-grade foundation walls, in excavations (cave-in protection — sloping/shoring per the excavation requirements, since workers are down in the excavation next to the wall) or confined spaces (confined-space procedures)), and the below-grade/confined-space controls. The below-grade-excavation/confined-space is the primary defining hazard — the work is below grade in excavations/confined spaces. (These follow the excavation and confined-space fundamentals.)
Bentonite-dust and slip
The dry bentonite dust and the wet-bentonite slip — the dust and slip hazards. The controls are bentonite-dust and slip controls (dry bentonite (granular/powder) generates dust when handled — a respiratory and eye irritant (and bentonite clay can contain some crystalline silica), so dust control and respiratory protection where dusty, and the slip hazard: wet bentonite is extremely slippery (bentonite is a clay that becomes very slick when wet), so if bentonite gets wet — from rain, groundwater, or activation — the surfaces become very slippery, a slip/fall hazard, requiring housekeeping, slip awareness, and keeping bentonite off walking surfaces), and the dust/slip controls. The bentonite-dust/slip is a defining hazard — dry bentonite is a dust and wet bentonite is very slippery. (These follow the dust and slip fundamentals.)
Material-handling and installation
Handling and installing the bentonite material — the handling hazard. The controls are safe material handling (the bentonite material (bags of granular bentonite, buckets of bentonite coating, or bentonite panels/rolls) — handling, manual-handling of the bags/materials), and the handling/installation controls. The material-handling/ installation is a defining hazard. (These follow the material-handling fundamentals.)
Eye
The eye (bentonite dust) carries the eye hazard. The controls are eye protection (bentonite dust is an eye irritant), and the eye controls. (These follow the eye-protection fundamentals.)
A simple Bentonite Waterproofing AHA structure
| Step | Hazard | Control | Standard |
|---|---|---|---|
| Assess | Confined space | Assess the location (excavation/confined space) | OSHA 1926.1200 |
| Protections | Cave-in | Set up excavation/confined-space protections | OSHA 1926.652 |
| Prepare | Dust | Prepare the surface | project |
| Apply | Dust / slip | Apply the bentonite waterproofing (dust control) | project |
| Protect | Slip | Protect the bentonite from premature wetting | project |
| Complete | Cave-in | Backfill or complete | project |
Excavation/confined-space safety and bentonite-dust/slip control
A Bentonite Waterproofing AHA centers on excavation/confined-space safety and bentonite-dust/slip control. The excavation/confined-space safety addresses the below-grade location — controlled by excavation and confined-space protections (cave-in protection, confined-space procedures). The bentonite-dust/slip control addresses the dry dust and the wet slip — controlled by bentonite-dust and slip controls (dust control and respiratory protection where dusty, slip awareness and housekeeping for wet bentonite), plus safe material handling. And the eye gets eye protection. An AHA built on excavation/confined-space safety and bentonite-dust/slip control, with handling controls, addresses the hazards that define bentonite waterproofing.
From the field: what actually goes wrong
In fourteen years across federal, heavy civil, and industrial projects, bentonite waterproofing applies sodium bentonite clay waterproofing to below-grade walls and foundations, and it heads the bentonite cluster with a notably different — and generally lower — hazard profile than the other waterproofing systems, because bentonite is a clay-based system with no solvents, no hot work, and no reactive isocyanate chemistry. The below-grade- excavation and confined-space hazard is a primary defining concern — like all the below-grade waterproofing, bentonite is applied against below-grade foundation walls, meaning working in excavations (where cave-in protection — sloping, shoring, or a protective system per the excavation requirements — is required, since workers are down in the excavation next to the wall) or confined spaces (confined-space procedures). The below-grade excavation and confined-space hazards are the defining location concern, and with bentonite they are not compounded by accumulating solvent vapors (a relative safety advantage).
The bentonite-dust/slip and the material-handling/installation are the other defining hazards, and they are bentonite-specific. On the projects I have run, dry bentonite (in granular or powder form) generates dust when handled, and this dust is a respiratory and eye irritant (and bentonite clay can contain some crystalline silica, so it warrants dust control and respiratory protection where the work is dusty), and — importantly — wet bentonite is extremely slippery, because bentonite is a clay that becomes very slick when it gets wet, so if bentonite gets wet from rain, groundwater, or activation, the surfaces (and the bottom of the excavation) become very slippery, a real slip and fall hazard, requiring housekeeping, slip awareness, and keeping bentonite off the walking surfaces. And the material-handling/installation hazard is handling the bentonite material (bags of granular bentonite, buckets of coating, or panels/rolls — manual handling). The eye hazard from bentonite dust rounds it out. The AHA built on excavation/confined-space safety and bentonite-dust/slip control is the one that protects the bentonite crew.
The bottom line
A Bentonite Waterproofing AHA names the below-grade-excavation/confined-space, the bentonite-dust/slip, and the material-handling/installation hazards with specific controls — excavation and confined-space protections (cave-in protection, confined-space procedures), bentonite-dust and slip controls (dust control and respiratory protection where dusty, slip awareness for the very slippery wet bentonite), and safe material handling. Unlike the solvent/ hot/reactive waterproofing, bentonite has no solvent-vapor, hot-work, or isocyanate hazards. The excavation/ confined-space safety and the bentonite-dust/slip control are the defining concerns. The AHA that manages both is the one that protects the crew.
Frequently asked questions
What below-grade hazards apply to bentonite waterproofing?
Bentonite is applied against below-grade foundation walls, meaning working in excavations (requiring cave-in protection per the excavation requirements) or confined spaces (requiring confined-space procedures); notably, unlike the solvent/hot/reactive waterproofing, bentonite does not add accumulating solvent vapors to the below-grade space. Controls are excavation and confined-space protections (cave-in protection, confined-space procedures), and the below-grade/confined-space controls.
What dust and slip hazards apply?
Dry bentonite (granular/powder) generates dust when handled — a respiratory and eye irritant (and bentonite clay can contain some crystalline silica) — and wet bentonite is extremely slippery (bentonite is a clay that becomes very slick when wet), a slip/fall hazard. Controls are bentonite-dust and slip controls (dust control and respiratory protection where dusty, slip awareness and housekeeping for wet bentonite, keeping bentonite off walking surfaces), and the dust/slip controls.
What handling hazards apply?
Handling the bentonite material (bags of granular bentonite, buckets of coating, or panels/rolls) is a manual-handling hazard. Controls are safe material handling, and the handling/installation controls.
What is bentonite waterproofing?
Bentonite waterproofing is the application of bentonite-clay waterproofing — the sodium bentonite clay waterproofing (applied as loose/granular bentonite, bentonite-based coatings, or in panel/sheet forms) that swells when wet to form a waterproof barrier, applied to below-grade walls, foundations, and structures. Because the work is below grade in excavations/confined spaces, dry bentonite is a dust and wet bentonite is very slippery, and the material is handled, those hazards apply (without the solvent/hot/reactive hazards of other systems).
Related AHAs and JHAs
- Bentonite Panel Waterproofing AHA — the bentonite panel form
- Bentonite Composite Sheet Waterproofing AHA — the bentonite composite sheet form
- Elastomeric Sheet Waterproofing AHA — the related sheet waterproofing
- Waterproofing Installation JHA — the waterproofing-installation fundamentals
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.