Authored by: Rimkus Forensics Marketing Team
OSHA’s Fatal Four (falls, struck-by incidents, electrocutions, and caught-in/between accidents) account for the majority of construction site fatalities each year. Construction recorded 1,034 fatal work injuries in 2024, down 3.8% from 1,075 in 2023, according to the Bureau of Labor Statistics ( BLS ). Falls alone accounted for 389 of these fatalities, and struck-by and caught-in/between incidents combined for another 161, together totaling 550, or 53%, of the year’s construction fatalities.
Construction continues to account for a substantial share of workplace fatalities despite long-running prevention and enforcement efforts. For claims professionals and risk managers, understanding the regulatory framework can help inform both prevention efforts and post-incident investigation.
This article walks through the Fatal Four and the other leading causes of construction accidents, the OSHA standards that govern each, and what the evidentiary record typically requires when an incident becomes a claim.
Key takeaways about the leading causes of construction accidents
Construction fatalities remain concentrated in a relatively small set of recognized hazard categories, many of which are addressed by specific OSHA standards and documentation requirements relevant to post-incident investigation.
What matters most
- OSHA’s Fatal Four hazards account for the largest share of construction fatalities each year.
- Each hazard traces to specific regulatory standards with documentation requirements that surface during claims.
- Falls remain the leading fatal hazard, with struck-by, electrocution, and caught-in/between events also representing major construction risks.
What claims teams should preserve
- Inspection logs, training records, and competent-person documentation may provide important evidence regarding site conditions and safety practices.
- Weather data, maintenance records, operator and signal-person qualifications, equipment records, and manufacturer information may be relevant to equipment-related incidents.
Rimkus supports construction incident investigations with forensic engineering expertise; contact us to discuss a case.
Understanding construction’s most serious hazards
OSHA refers to these categories as the “Fatal Four” (the agency’s current outreach materials use the name “Focus Four” for the same categories), and they consistently represent a significant share of serious injuries and workplace safety violations across the industry. From a forensic perspective, these incidents tend to be preventable, typically involve multiple regulatory violations, and generate substantial liability exposure. However, other causes of construction incidents occur with similar frequency and warrant equal attention.
1. Falls from heights
Falls caused 389 of construction’s 1,034 fatalities in 2024 — 37.6% — and 48.8% of all fatal falls across U.S. private industry ( BLS ). 29 CFR 1926.501 establishes fall-protection requirements for specified construction activities, commonly beginning at six feet above a lower level, while 1926.502 establishes criteria for systems such as guardrails and personal fall arrest systems. 29 CFR 1926.503 addresses fall-hazard training requirements, including required certification of training.
Investigators may evaluate the personal fall arrest system, anchorage, guardrails, equipment condition, scene configuration, and applicable fall-protection requirements. Scene photographs, equipment and inspection records, training documentation, and information about the system’s design and installation may help establish the conditions present at the time of the incident.
2. Struck-by incidents
Struck-by incidents involve flying objects, falling materials, swinging loads, and rolling equipment — one of the Fatal Four. 29 CFR 1926.1428 requires crane signal persons to pass both an oral/written and a practical exam. Crane-disassembly investigations commonly examine whether the employer followed manufacturer procedures, completed required planning, assessed weather conditions, and used the personnel required for the task; the facts may support citations of varying classifications depending on the employer’s knowledge and conduct. 29 CFR 1926.601 requires daily vehicle inspections.
A vehicle-strike investigation usually opens with the pre-shift inspection sheet, telematics data, and the operator’s training file to determine whether a known defect or an unqualified operator went uncorrected. A crane event adds the lift plan, wind records, and signal-person qualification documents, then compares the disassembly sequence actually used against the manufacturer’s procedure.
3. Electrocutions
Exposure to electricity caused 130 worker fatalities nationwide in 2024, down from 142 in 2023, according to BLS . 29 CFR 1926.1408 establishes requirements for equipment operations near power lines, including a 10-foot minimum clearance option for lines up to 50 kV under specified circumstances; other requirements and clearance distances apply depending on voltage, operation, and the measures selected. Employers must implement GFCI protection or an assured grounding program under 1926.404(b)(1) , which applies to 120-volt, single-phase, 15- and 20-ampere receptacles not part of permanent wiring. NFPA 70E sets voltage-specific approach boundaries; confirm the applicable table rather than assuming a single fixed distance.
Investigations typically start with utility locates, the one-line diagram, and the equipment’s position at the time of contact, then check whether GFCI or an assured grounding program was in place and inspected on the circuit involved. Confirming line voltage, equipment position and configuration, applicable clearance requirements, and the measures used to prevent encroachment can help investigators evaluate the circumstances of an electrical-contact incident.
4. Caught-in/between hazards
Excavations 5 feet deep or greater generally require an adequate protective system 29 CFR 1926.652 unless the excavation is made entirely in stable rock, while shallower excavations may also require protection when a competent person identifies a potential cave-in hazard. A competent person has specified responsibilities for identifying hazards and taking prompt corrective measures under OSHA’s excavation requirements.
Excavation investigations may include competent-person documentation, soil-classification information, inspection records, protective-system design or tabulated data, site photographs, weather conditions, and evidence of changing excavation conditions. 29 CFR 1926.300 separately requires guards on moving machine parts, a frequent co-occurring citation; investigators check whether a guard had been removed for maintenance and never restored.
5. Scaffolding and ladder violations
Scaffolding (29 CFR 1926.451) ranked sixth among OSHA’s most frequently cited standards in final FY2025 data, and scaffold and ladder incidents sit within the 95.9% of construction’s fatal falls, slips, and trips in 2024 that were falls to a lower level (the same BLS analysis cited above). Erection, dismantling, and inspection require a competent person’s direction; certain configurations must be designed by a qualified person under 29 CFR 1926.451 . Non-self-supporting ladders must be set at roughly 75½ degrees from horizontal per 1926.1053(b)(5)(i) , with side rails extending at least 3 feet above the landing or secured with a grab rail.
Investigators separate the two roles the standard creates: whether a qualified person actually designed the configuration used, and whether a competent person directed erection and performed the pre-shift inspection. For ladder falls, investigators may evaluate ladder angle, side-rail extension, footing, condition, placement, and other relevant requirements using scene measurements, photographs, witness information, and physical evidence where available.
6. Equipment and machinery failures
Equipment incidents may involve maintenance conditions, operation, component failure, design or manufacturing issues, environmental conditions, or combinations of factors requiring appropriate technical investigation. Construction reported 1,468 severe-injury hospitalizations and 231 amputations to OSHA in 2024 across all causes; that’s broader than equipment failures alone, but amputations in particular frequently trace to machinery and equipment contact, making it a useful current benchmark.
29 CFR 1926.601 mandates beginning-of-shift inspections of brakes, tires, steering, and safety devices. Industrial trucks must meet ANSI B56.1-1969 design and maintenance requirements under 1926.602 .
Investigations may review maintenance and inspection records, OEM service information, parts-replacement history, operating data, and the condition of failed components to evaluate potential failure mechanisms and contributing factorst.
7. Hazardous energy and lockout/tagout failures
Lockout/Tagout isolates equipment from energy sources during maintenance and ranked 4th among OSHA’s most frequently cited standards in final FY2025 data (the same list cited in the scaffolding section above). Construction work may implicate 29 CFR 1926.417 ‘s construction-specific tagging requirements and, depending on the activity and equipment involved, 1910.147 ‘s hazardous-energy-control requirements. Under 1910.147, lockout devices must withstand their exposure environment for the expected duration.
Investigations typically request the written energy-control procedure, the authorized-employee training file, the periodic LOTO audit log, and the lock/tag assignment record for the specific machine involved, then verify whether the procedure on paper actually matched the lockout points used on the equipment as found.
8. Slips, trips, and same-level falls
Falls, slips, and trips are a frequent source of nonfatal construction injuries: per the same BLS analysis, private construction recorded 30.0 such cases per 10,000 full-time workers in 2024, compared with 22.6 across private industry. 29 CFR 1926.25 requires debris and protruding-nail lumber cleared from work areas, passageways, and stairs, with regular removal of combustible scrap.
Same-level fall investigations may consider housekeeping conditions, site photographs, walking-surface characteristics, lighting, weather or moisture, footwear, work activities, prior reports, and other evidence relevant to the incident. Contemporaneous documentation can help establish conditions at or near the time of the event .
9. Weather and environmental conditions
Federal OSHA currently does not have a final construction-specific heat standard. OSHA addresses heat hazards through existing authority, enforcement initiatives, and guidance, while state-plan requirements may differ. Heat-index values and recommended protective measures can help inform hazard evaluation but should be interpreted within the applicable regulatory and site-specific context. For personnel-platform lifts, 29 CFR 1926.1431 requires a qualified-person wind assessment above 20 mph. The standard lightning practice, 30 minutes clear after last thunder, is guidance, not a fixed OSHA rule.
Rimkus forensic meteorology analysis can reconstruct weather conditions at the time and location of an incident using available site observations, weather-station data, radar, and other appropriate sources. Those findings may then be compared with applicable regulations, project procedures, manufacturer requirements, or industry guidance relevant to the activity being evaluated.
10. Human factors
OSHA research links working 12-hour shifts to a 37% increased injury risk , with risk climbing further as shifts extend. Timecards, schedule records, and overtime logs can help establish whether fatigue contributed to an incident. 29 CFR 1926.21 requires appropriate training and instruction for all employees.
Human-factors investigations may consider shift duration, rest opportunities, time of day, sleep-wake history, workload, training, communication, and other factors that may affect performance. Training records and information about how instructions were communicated may also be relevant when evaluating whether workers received and understood applicable safety information.
Fatal Four prevention checklist
Translating the Fatal Four and related high-risk hazards into a single reference makes daily compliance checks practical for site supervisors, and this checklist is designed to be printed and posted on the job trailer.
Fatal Four Controls
- Falls: Verify applicable guardrail and personal fall arrest system requirements, including anchorage criteria
- Struck-By: Signal person dual testing, daily vehicle inspection records
- Electrocutions: Verify applicable power-line clearance and encroachment-prevention requirements; provide required GFCI or assured equipment grounding protection
- Caught-In/Between: Evaluate excavation hazards, protective-system requirements, soil conditions, and competent-person inspections
High-Risk Controls
- Scaffold: Trained personnel under competent-person direction; inspect before each shift
- Heat: Evaluate heat conditions, protective measures, applicable OSHA requirements and guidance, and state-plan requirements
- Lighting: Follow the site’s applicable lightning-safety plan and recognized safety guidance before resuming outdoor work
This checklist can provide a high-level reference for common hazards but does not replace review of the regulations, manufacturer requirements, site-specific safety plans, or other requirements applicable to the work.
How Rimkus supports construction safety programs
Rimkus supports construction incident investigations with forensic engineering services that may include: 3D laser scanning for scene documentation, crane and rigging engineering analysis, power line proximity calculations, geotechnical soil classification reviews, and materials testing laboratories. These capabilities can help claims professionals, risk managers, and counsel understand the technical conditions and factors relevant to an incident.
Frequently asked questions about construction accident causes
What are the OSHA Fatal Four hazards in construction?
The Fatal Four hazards are falls, struck-by incidents, electrocutions, and caught-in/between accidents; OSHA’s current outreach materials also refer to these categories as the “Focus Four.” Falls alone represented 37.6% of construction fatalities in 2024, while falls combined with struck-by and caught-in/between incidents accounted for more than half before electrocutions were added.
How long do employers have to report construction accidents to OSHA?
Employers must report work-related fatalities within eight hours and work-related inpatient hospitalizations, amputations, or losses of an eye within 24 hours. These duties generally apply when a fatality occurs within 30 days of the incident, or when a hospitalization, amputation, or eye loss occurs within 24 hours of it. Failure to report within required timeframes can result in additional citations and penalties beyond those related to the underlying incident.
What documentation should be preserved after a construction accident?
Relevant documentation may include daily inspection logs, training records, competent-person documentation, equipment maintenance records, weather data, work schedules, site photographs, and other incident-specific records. For crane incidents, signal-person qualification records, lift documentation, equipment records, and qualified-person assessments may also be relevant. Early evidence preservation can help maintain records and physical evidence that might otherwise be lost, altered, or overwritten
With 40+ years of experience and a network of 900+ experts across 100+ offices, Rimkus can help with construction safety investigations. Contact Rimkus today for a consultation.
This article is intended to provide general information and insights into prevailing industry practices. It is not intended to constitute, and should not be relied upon as, legal, technical, or professional advice. The content does not replace consultation with a qualified expert or professional regarding the specific facts and circumstances of any particular matter.