21 Essential Accident, Incident and EHS KPIs

Accident and Incident Key Performance Indicators (KPIs) are critical tools for evaluating workplace safety performance, identifying trends, preventing repeat incidents, and demonstrating regulatory compliance. In modern Health, Safety, and Environment (HSE) management systems, KPIs go beyond numbers — they drive behavior, guide leadership decisions, and reflect the true safety culture of an organization.

This comprehensive guide explains 21 essential Accident, Incident, and EHS KPIs, how to calculate them, how to interpret results correctly, and how organizations can use them to improve real-world safety performance.

A. Accident / Incident KPIs

1. Total Incident Rate (TIR)

Formula:
Total Incident Rate (TIR) = (Total recordable cases × 1,000,000) ÷ Total man-hours worked

Total Incident Rate is one of the most widely used safety performance indicators across industries. It measures the overall number of recordable incidents relative to exposure hours worked, allowing organizations to compare safety performance across projects, contractors, or even countries.

A high TIR indicates frequent incidents and often signals gaps in hazard identification, supervision, training, or safety leadership. However, TIR should never be interpreted in isolation. A low TIR may sometimes reflect under-reporting rather than genuine safety improvement.

From a practical perspective, organizations should analyze TIR trends over time rather than focusing on a single reporting period. Sudden increases may indicate operational changes, workforce turnover, or process failures. Reducing TIR requires proactive controls such as behavior-based safety programs, job hazard analysis, and a strong incident reporting culture.

2. Lost Time Injury Frequency Rate (LTIFR)

Formula:
LTIFR = (Lost time injury cases × 1,000,000) ÷ Total man-hours worked

LTIFR measures how often serious injuries occur that result in employees being unable to return to work for at least one full shift. It is a critical metric used by regulators, insurers, and clients to assess the severity of workplace safety risks.

A rising LTIFR often indicates high-risk activities, ineffective controls, or inadequate supervision. Industries such as construction, oil and gas, and mining closely track LTIFR because it directly reflects life-altering injuries.

Reducing LTIFR requires a focus on high-risk tasks, permit-to-work systems, lockout-tagout, working at height controls, and competency management. Organizations with strong safety cultures typically emphasize prevention of high-consequence events rather than chasing zero numbers.

3. Lost Time Injury Severity Rate (LTISR)

Formula:
LTISR = (Total lost workdays × 1,000,000) ÷ Total man-hours worked

While LTIFR shows how often lost time injuries occur, LTISR measures how severe those injuries are. It captures the total number of days lost due to work-related injuries, providing deeper insight into the impact on productivity and worker wellbeing.

A high LTISR suggests that injuries are not only frequent but also severe, possibly indicating poor emergency response, delayed medical treatment, or ineffective return-to-work programs.

Organizations should investigate LTISR spikes carefully. Root cause analysis often reveals deficiencies in machine guarding, ergonomics, contractor control, or fatigue management. Effective medical management, early rehabilitation, and modified duties programs can significantly reduce severity rates even when injuries occur.

4. Accident Frequency Rate (AFR)

Formula:
AFR = (Total accidents × 1,000,000) ÷ Total man-hours worked

Accident Frequency Rate tracks how often accidents occur regardless of injury outcome. This includes property damage incidents, equipment damage, and operational accidents that may not result in personal injury.

AFR is useful for identifying unsafe processes and poor operational discipline. A high AFR may indicate inadequate maintenance, unsafe driving behavior, or poor traffic management within facilities.

Reducing AFR requires strong preventive maintenance programs, standard operating procedures, toolbox talks, and enforcement of safe work practices. AFR trends often improve when organizations encourage near-miss reporting, as early identification of hazards prevents accidents from escalating.

5. Accident Severity Rate (ASR)

Formula:
ASR = Total lost days ÷ Total accidents

Accident Severity Rate measures the average seriousness of accidents by calculating the number of lost days per accident. Unlike frequency-based KPIs, ASR focuses on consequence rather than occurrence.

A low accident frequency with a high severity rate is a warning sign that, while accidents are rare, they are severe when they do occur. This is common in high-risk industries where single events can have catastrophic outcomes.

Organizations should use ASR to prioritize high-consequence risk controls such as engineering safeguards, fail-safe systems, and emergency preparedness. Leadership attention should focus not only on reducing accident numbers but also on minimizing harm when incidents occur.

B. Man-days Loss & Near Miss KPIs

6. Man-days Lost (MDL)

Formula:
Man-days Lost = Σ(Number of days each injured worker is absent)

Man-days Lost quantifies the total impact of injuries on workforce availability. It translates safety failures into operational and financial consequences that management can easily understand.

High MDL affects productivity, morale, overtime costs, and project timelines. It also reflects the human cost of injuries on workers and their families.

Organizations should analyze MDL by injury type, department, and activity to identify patterns. Effective return-to-work programs, early medical intervention, and ergonomic improvements are proven strategies for reducing lost days while supporting injured employees.

7. Near Miss Frequency Rate (NMFR)

Formula:
NMFR = (Number of near misses × 1,000,000) ÷ Total man-hours worked

Near Miss Frequency Rate measures how often potential incidents are identified before causing harm. Unlike injury rates, a high NMFR is often positive, indicating a strong reporting culture and proactive hazard identification.

Organizations with mature safety systems encourage near-miss reporting without fear of blame. These reports provide valuable learning opportunities and prevent serious accidents.

Low near-miss reporting may indicate fear of punishment, lack of awareness, or poor leadership engagement. Improving NMFR requires training, anonymous reporting options, and visible corrective actions to show workers that reporting leads to real improvements.

8. Unsafe Act Frequency Rate (UA-FR)

Formula:
UA-FR = (Number of unsafe acts × 1,000,000) ÷ Total man-hours worked

Unsafe Act Frequency Rate measures how often workers engage in behaviors that violate safety rules or best practices. Examples include bypassing guards, not using PPE, or taking shortcuts.

High UA-FR often points to behavioral, cultural, or leadership issues rather than a lack of rules. Workers may understand procedures but choose not to follow them due to time pressure or poor supervision.

Behavior-based safety programs, positive reinforcement, and leadership visibility are effective tools for reducing unsafe acts. The goal is not punishment but changing attitudes and reinforcing safe choices consistently.

9. Unsafe Condition Frequency Rate (UC-FR)

Formula:
UC-FR = (Number of unsafe conditions × 1,000,000) ÷ Total man-hours worked

Unsafe Condition Frequency Rate focuses on physical hazards such as defective equipment, poor housekeeping, inadequate lighting, or exposed electrical components.

A high UC-FR indicates failures in maintenance, inspections, or management of change. Unlike unsafe acts, unsafe conditions are often management-controlled and require systemic solutions.

Regular inspections, preventive maintenance schedules, and worker involvement in hazard identification significantly reduce unsafe conditions. Tracking UC-FR helps organizations shift from reactive fixes to proactive hazard elimination.

C. EHS Performance, Compliance and Health Metrics

10. Safety Performance Index (SPI)

Formula:
SPI = (Total safe observations ÷ Total observations) × 100

Safety Performance Index measures the proportion of safe behaviors observed during inspections or safety walks. It reflects day-to-day operational discipline and workforce engagement.

A high SPI indicates that safety rules are understood and followed, while a declining SPI may signal complacency or normalization of risk.

SPI should be used as a coaching tool rather than a disciplinary metric. Providing immediate feedback, recognizing safe behaviors, and involving supervisors in observations strengthens safety culture and drives continuous improvement.

11. Audit Score (%)

Formula:
Audit Score = (Points scored ÷ Total possible points) × 100

Audit Score evaluates compliance with legal requirements, standards such as ISO 45001, and internal procedures. It provides structured insight into system effectiveness.

A high audit score demonstrates strong governance, while repeated low scores indicate systemic weaknesses. However, passing audits alone does not guarantee safe operations.

Organizations should focus on closing audit findings promptly and preventing recurrence. Audit results should feed into management review meetings and improvement plans rather than being treated as one-time exercises.

12. PPE Compliance (%)

Formula:
PPE Compliance = (Workers wearing required PPE ÷ Workers checked) × 100

PPE Compliance measures adherence to personal protective equipment requirements. While PPE is the last line of defense, non-compliance exposes workers to immediate harm.

Low compliance may result from discomfort, poor fit, lack of availability, or weak enforcement. Simply issuing PPE is not enough.

Improving compliance requires worker involvement in PPE selection, regular training, leadership role-modeling, and enforcement consistency. PPE compliance rates are often a direct reflection of site supervision quality.

13. Occupational Injury Rate

Formula:
Occupational Injury Rate = (Recordable injuries × 1,000,000) ÷ Total man-hours worked

This KPI focuses on work-related injuries that meet reporting criteria. It is commonly used for regulatory reporting and benchmarking.

A rising occupational injury rate suggests increasing exposure to hazards or weakening controls. Analysis by job role, task, and location helps identify root causes.

Preventive strategies include ergonomic assessments, job rotation, and improved hazard controls. Accurate reporting is essential for this KPI to remain meaningful.

14. Injury Rate (All Injuries)

Formula:
Injury Rate = (Total injuries × 1,000,000) ÷ Total man-hours worked

Unlike recordable injury rates, this metric includes all injuries, regardless of severity. It provides a broader view of worker health and safety.

High minor injury rates may indicate poor housekeeping, inadequate training, or unsafe tools. Addressing these issues early prevents escalation into serious incidents.

Tracking all injuries supports proactive safety management and aligns with the principle that serious accidents often have multiple warning signs.

15. First-Aid Case Rate

Formula:
First-Aid Case Rate = (First-aid cases × 1,000,000) ÷ Total man-hours worked

First-aid cases are early indicators of safety performance. While often considered minor, frequent first-aid cases signal underlying hazards.

Ignoring first-aid trends can allow risks to escalate into lost-time injuries. Effective organizations investigate first-aid cases with the same seriousness as recordable injuries.

Improving workplace ergonomics, housekeeping, and task design often leads to significant reductions in first-aid cases.

D. Fire Safety, Behavior & Resource KPIs

16. Fire Load Density

Formula:
Fire Load Density = Total heat potential of combustibles (MJ) ÷ Floor area (m²)

Fire Load Density measures the potential severity of a fire within a space. High fire load increases fire intensity and risk to life and property.

Understanding fire load density helps in designing appropriate fire protection systems, compartmentation, and emergency response plans.

Reducing fire load involves controlling combustible materials, improving storage practices, and housekeeping. This KPI is critical in warehouses, manufacturing plants, and commercial buildings.

17. Fire Risk Priority Number (RPN)

Formula:
Fire RPN = Severity × Occurrence × Detection

Fire Risk Priority Number is derived from risk assessment principles and helps prioritize fire risks. Higher RPNs demand immediate attention.

This metric enables objective comparison of fire risks and supports resource allocation. Reducing RPN can be achieved by lowering severity, likelihood, or improving detection systems.

Regular review of fire RPN ensures evolving risks are addressed proactively.

18. Action Closure Rate (%)

Formula:
Action Closure Rate = (Actions closed ÷ Actions raised) × 100

Action Closure Rate reflects management commitment to safety improvements. Raising actions without closing them undermines safety credibility.

Low closure rates indicate poor accountability or resource constraints. High closure rates demonstrate leadership engagement and effective follow-through.

Tracking this KPI ensures that identified risks are not ignored and that continuous improvement remains active.

19. Safe Behavior Rate (%)

Formula:
Safe Behavior Rate = (Safe behaviors ÷ Total behaviors observed) × 100

Safe Behavior Rate measures how consistently workers follow safe practices. It is a leading indicator of safety culture maturity.

A declining safe behavior rate often precedes incidents. Addressing behavioral drift early prevents accidents.

Positive reinforcement, peer observation, and leadership engagement are key drivers of sustained safe behavior.

20. Water Consumption per Man-hour

Formula:
Water Consumption per Man-hour = Total water used ÷ Total man-hours worked

This KPI links environmental performance with workforce activity. High water consumption may indicate inefficiencies or leaks.

Monitoring water usage supports sustainability goals and regulatory compliance. It also reflects responsible resource management.

Reducing water consumption requires awareness campaigns, efficient systems, and regular monitoring.

E. Man-hour Calculation

21. Total Man-hours Worked

Formula:
Total Man-hours = Workers × Hours per day × Days worked

Total man-hours worked is the foundation of all frequency-based KPIs. Accuracy is critical, as errors distort every calculated rate.

Organizations must include overtime, contractor hours, and shift variations. Consistent man-hour tracking ensures reliable benchmarking and performance analysis.

Strong data integrity underpins credible safety performance reporting.

Conclusion

Accident and Incident KPIs are powerful tools when used correctly. They should drive learning, prevention, and improvement, not fear or under-reporting. Organizations that balance lagging indicators with leading metrics build stronger safety cultures, reduce serious injuries, and achieve sustainable performance.

Effective safety measurement is not about chasing numbers — it is about protecting people, improving systems, and making informed decisions based on reliable data.