Construction term · Glossary
Struck-By Hazard
One of OSHA's construction “Focus Four” hazards — injury or death from being hit by a moving object. OSHA groups struck-by into four types: flying (e.g., from a tool or grinder), falling (dropped or wind-blown objects), swinging (loads, booms), and rolling (vehicles, equipment). If the impact alone caused the injury, it's struck-by (not caught-in/between).
Also known as: struck-by object
On this page
Struck-By Hazard at a glance
- Four types: flying, falling, swinging, and rolling objects.
- The test vs. caught-in: if the IMPACT caused the injury, it's struck-by.
- One of the “Focus Four” causes of construction death (a leading cause).
- Controls: hard hats, toe boards/debris nets, secured loads, spotters, and exclusion zones.
In plain English
Getting hit by something that's moving — a dropped tool, a flying chip, a swinging load, or a backing vehicle. If the impact is what hurt you, it's struck-by. It's one of construction's top four killers.
What the source says, in summary
Struck-by injuries are produced by forcible contact or impact between the injured person and an object or piece of equipment. They are categorized as struck-by flying, falling, swinging, or rolling objects.
In context
A concept governed primarily by OSHA's construction standards, 29 CFR Part 1926 — the rules that apply on jobsites rather than the general-industry 1910 set.
Example
A worker below a scaffold is hit by a dropped wrench — a struck-by (falling object) injury the toe board and hard hat exist to prevent. A vehicle backing without a spotter that strikes a worker is struck-by (rolling object).
Why it matters
Struck-by is one of the most common construction fatalities, and its causes — unsecured objects at height, unspotted equipment, unguarded tools — are everyday jobsite conditions. As a Focus Four hazard, controlling it (toe boards, spotters, exclusion zones, PPE) targets a major share of preventable injuries.
Struck-by vs. caught-in/between
OSHA's test: if the injury came from the IMPACT of a moving object, it's struck-by. If it came from being CRUSHED or compressed between objects, it's caught-in/between. A swinging load that hits you is struck-by; being pinned by that load against a wall is caught-in/between.
The four types of struck-by hazard
| Type | Example |
|---|---|
| Flying object | Chip or fragment from a grinder or nail gun |
| Falling object | Tool or material dropped from height |
| Swinging object | Suspended load or crane boom |
| Rolling object | Vehicle or equipment moving on the ground |
Struck-By Hazard: frequently asked questions
- What are the four types of struck-by hazards?
- Flying objects (e.g., from a grinder or nail gun), falling objects (dropped from height), swinging objects (loads and booms), and rolling objects (vehicles and equipment).
- How is struck-by different from caught-in/between?
- OSHA's test: if the impact of a moving object caused the injury, it's struck-by; if crushing or compression between objects caused it, it's caught-in/between.
- How do you prevent struck-by injuries?
- Hard hats, toe boards and debris nets to stop falling objects, securing loads, using spotters and exclusion zones around equipment, and keeping workers out of swing and travel paths.
Related terms
Free tools for this
Governing OSHA standards
More Construction terms
The part of Title 29 of the Code of Federal Regulations that contains OSHA's General Industry standards — the default rulebook for most American workplaces (manufacturing, warehousing, healthcare, etc.) that aren't covered by the construction, maritime, or agriculture standards. It includes core rules like Hazard Communication (1910.1200) and the permissible exposure limits (1910.1000). Several 1910 standards are cross-referenced into construction via Part 1926.
29 CFR 1926The part of Title 29 of the Code of Federal Regulations that contains OSHA's Construction standards — the “Safety and Health Regulations for Construction.” It governs construction, alteration, and repair work, with construction-specific rules for fall protection (Subpart M), scaffolds (Subpart L), excavations (Subpart P), electrical (Subpart K), and more. Where a task isn't addressed in 1926, some general-industry (1910) standards apply by reference.
Anchor PointThe secure attachment point a personal fall arrest system (PFAS) ties off to — the “A” in the ABC of fall arrest. Under 29 CFR 1926.502(d)(15), a non-engineered anchorage must support at least 5,000 pounds per attached worker; alternatively, it can be an engineered anchorage designed and supervised by a qualified person with a safety factor of at least two.
Atmospheric TestingMeasuring the air in a confined space (or other hazardous atmosphere) with a calibrated direct-reading instrument before and during entry. OSHA requires testing in a set order — oxygen first, then flammable gases and vapors, then potential toxic contaminants — and defines the acceptable ranges: oxygen 19.5%–23.5%, flammables below 10% of the LEL, toxics below their exposure limits.
BenchingAn excavation cave-in protective system that cuts the sides into a series of horizontal steps (benches), usually with vertical or near-vertical faces between levels. It's one of OSHA's accepted protective systems under Subpart P — but it is NOT permitted in Type C (the least stable) soil.
Competent Person (Excavation)The competent person OSHA's excavation standard (Subpart P) requires on every trenching job — someone trained in soil classification and protective systems, who can identify cave-in and other hazards AND has authority to remove workers and correct problems. They must inspect the excavation daily before work starts, throughout the shift, and after any rain or event that could increase the hazard.
Confined SpaceA space that is large enough for a worker to bodily enter, has limited or restricted means of entry or exit, and is not designed for continuous occupancy. If it also contains — or could contain — a serious hazard (a hazardous atmosphere, engulfment material, an entrapping configuration, or any other recognized serious hazard), it becomes a permit-required confined space (PRCS).
Controlling EmployerUnder OSHA's Multi-Employer Citation Policy (CPL 02-00-124), the controlling employer is an employer with general supervisory authority over a worksite — including the power to correct safety and health violations itself or to require others to correct them. This is typically the general contractor or construction manager. A controlling employer can be cited for a hazard at the site even if none of its own employees are exposed, because it has a duty to exercise reasonable care to prevent and detect violations by the other employers on site.
Sources & verification
Reviewed by HazComFast against eCFR, OSHA.gov, NIOSH, and the Federal Register. Last reviewed 2026-10-05. This glossary is general information, not legal advice; OSHA State-Plan states (e.g. California, Michigan) may adopt stricter requirements.
Put Struck-By Hazard into practice
Don't just read the definition — apply it. Use the free PPE Selector by GHS Pictogram to put real numbers behind Struck-By Hazard for your jobsite.
Get the Binder in Order Before the Inspector Arrives. Are You Ready?
OSHA does not give advance notice of inspections (29 CFR 1903.6). Get the binder in order before the opening conference, not during it.
Serious Violation
$16,550
per violation (max)
HazComFast Pro
$199/mo
10 jobsites, unlimited chemicals, unlimited workers
New sign-ups are paused. The free tools below need no account, and customers can log in as usual.
Your account keeps working as usual. Cancel anytime.