Industrial Engineer Industrial Safety cheat sheet

A safety management system (SMS) is a documented, auditable framework of policy, planning, implementation, evaluation, and corrective action; ISO 45001 uses the Plan-Do-Check-Act (PDCA) cycle as its structural logic.

ISO 45001:2018 clauses: 4 Context, 5 Leadership and worker participation, 6 Planning, 7 Support, 8 Operation, 9 Performance evaluation, 10 Improvement; clauses 4–10 are the auditable requirements.

Hierarchy of controls, highest to lowest: elimination, substitution, engineering controls, administrative controls, PPE; controls are selected in that order and PPE is the last resort.

ANSI/ASSP Z10 is a US consensus SMS standard; it uses a similar PDCA structure but is not a certification standard in the way ISO 45001 is.

Management review is a top-management activity with defined inputs (audit results, incident data, objectives status, worker consultation) and outputs (decisions on resources, objectives, changes).

Leading indicators measure preventive activity (inspections completed, training hours, near-miss reports); lagging indicators measure outcomes (recordable rate, lost-time rate, fatalities).

A written SMS must define roles, responsibilities, and accountability down to the supervisor level; accountability without matching authority is a common audit finding.

Document control requires that current versions be identifiable and obsolete versions prevented from unintended use; controlled documents carry revision status and approval.

In the US, OSHA general industry rules are in 29 CFR 1910; construction in 29 CFR 1926; the General Duty Clause (OSH Act Section 5(a)(1)) covers recognized hazards with no specific standard.

OSHA recordkeeping: 29 CFR 1904 requires recording of fatalities, and of injuries/illnesses meeting criteria such as days away, restricted work, or medical treatment beyond first aid; first aid alone is not recordable.

29 CFR 1910.147 is the Lockout/Tagout standard; 1910.212 is general machine guarding; 1910.219 covers mechanical power-transmission apparatus.

29 CFR 1910.134 is respiratory protection; 1910.1000 contains the air contaminant permissible exposure limits (PELs) tables Z-1, Z-2, Z-3.

NFPA 70 is the National Electrical Code; NFPA 70E covers electrical safety in the workplace; NFPA 30 covers flammable and combustible liquids; NFPA 101 is the Life Safety Code.

ISO 45001 is a certifiable occupational health and safety management system standard; ISO 14001 covers environmental management; ISO 9001 covers quality.

OSHA permissible exposure limits are 8-hour time-weighted averages unless marked as a ceiling; ACGIH threshold limit values (TLVs) are consensus guidelines, not legal limits.

ANSI/ASSP consensus standards (for example Z244.1 for lockout/tagout and alternative methods, B11 series for machine tools) become enforceable when incorporated by reference into a regulation or adopted by an employer.

Hazard is a potential source of harm; risk is the combination of the likelihood of occurrence of harm and the severity of that harm.

Hazard identification methods include task-based job hazard analysis (JHA), hazard and operability study (HAZOP), failure mode and effects analysis (FMEA), what-if analysis, and checklists.

HAZOP uses guide words (no, more, less, as well as, part of, reverse, other than) applied to process parameters (flow, pressure, temperature, level) to find deviations.

The energy-release model classifies hazards by energy type: kinetic, potential, electrical, thermal, chemical, radiation, biological, and pressure.

Near-miss reporting is a leading-indicator source of hazard information; unreported near misses predict future incidents.

Change analysis (management of change) identifies new hazards introduced by process, equipment, personnel, or material changes.

A job hazard analysis breaks a task into steps, identifies hazards per step, and specifies controls per step; it is most useful for tasks with a history of incidents or high-severity potential.

Preliminary hazard analysis (PHA) is performed early in design, before detailed design information exists, and ranks hazards by severity and probability.

Risk score = likelihood × severity in a typical risk matrix; matrix size (3×3, 4×4, 5×5) determines granularity, and the same hazard can score differently on different matrices.

ALARP means As Low As Reasonably Practicable; residual risk is acceptable when further reduction is grossly disproportionate to the benefit.

Quantitative risk assessment uses frequency (events per year) and consequence (fatalities per event) to compute individual risk, often compared to a tolerable limit such as 1×10⁻⁶ per year for the public and 1×10⁻³ per year for workers in some jurisdictions.

Risk treatment options, in hierarchy order: avoid the risk, reduce likelihood, reduce severity, transfer (insurance), and accept with documented rationale.

Bow-tie analysis links threats and preventive barriers on the left to consequences and mitigating barriers on the right, with the top event in the center.

Residual risk after controls must be re-evaluated; controls can introduce new hazards (for example, guarding can create a maintenance access hazard).

Risk acceptance criteria must be defined before assessment, not adjusted after results are known, to avoid bias.

Layers of protection analysis (LOPA) estimates the risk reduction of independent protection layers and compares the mitigated frequency to a target.

NIOSH lifting equation: recommended weight limit RWL = LC × HM × VM × DM × AM × FM × CM; the lifting index LI = load weight / RWL, and LI > 1.0 indicates increased risk.

The NIOSH equation constants: load constant LC = 23 kg (51 lb); the equation applies to two-handed, smooth lifting without carrying, pushing, or pulling.

Anthropometric design rule: design for the 5th percentile for reach and clearance limits, and the 95th percentile for clearance and strength demands.

Repetitive motion risk factors: high repetition, high force, awkward posture, vibration, and insufficient recovery time; these combine multiplicatively rather than additively.

The ACGIH hand-activity level (HAL) and threshold limit value for hand-arm vibration are used to evaluate exposure to vibrating tools.

Cognitive human factors: workload, vigilance decrement, and automation complacency; error rates rise when operators monitor automated systems passively for long periods.

Control-display compatibility: controls should be arranged to match the display or process layout, and emergency controls should be distinguishable by shape, size, and location.

A comfort zone for seated work uses an elbow angle near 90–110 degrees, forearms roughly horizontal, and feet supported; monitor top near or slightly below eye level.

29 CFR 1910.212(a)(1): one or more methods of machine guarding shall be provided to protect the operator and other employees from hazards such as those created by point of operation, ingoing nip points, rotating parts, flying chips, and sparks.

Point-of-operation guards must prevent the operator's hands, arms, or other body parts from entering the danger zone during the operating cycle; barrier guards, interlocked gates, and presence-sensing devices are common types.

A fixed barrier guard requires no movement to function and needs a tool to remove; an interlocked guard stops the hazardous motion when the guard is opened.

Safety distance for presence-sensing devices: D = K × T, where K is the approach speed (commonly 63 in/s or 1600 mm/s) and T is the total stopping time including device response.

Two-hand control requires both hands on controls during the hazardous portion of the cycle; it does not protect against entry by other persons unless combined with other safeguards.

Guards must not create new hazards: no sharp edges, no pinch points, no interference with required visibility, and no trapping of chips or coolant.

A guard opening must be sized so that the body part it is meant to exclude cannot reach the hazard; use the ANSI B11.19 opening-to-distance tables for the specific opening size.

Periodic inspection of guards and interlocks is required; defeated or removed guards are among the most frequently cited machine-guarding violations.

29 CFR 1910.147 applies to servicing and maintenance where unexpected energization or release of stored energy could injure; normal production operation is excluded.

The six-step LOTO sequence: notify affected employees, shut down, isolate all energy sources, apply locks and tags, release stored energy (bleed, drain, block, ground), and verify isolation by attempting startup or testing.

Each authorized employee applies a personal lock; group lockout uses a lockout device or hasp so that each worker retains a personal lock until their work is complete.

Lockout is the primary method; tagout alone is permitted only when the energy-isolating device cannot be locked out, and the employer must demonstrate equivalent protection.

NFPA 70E establishes arc flash and shock risk assessment, arc-rated PPE selection, and approach boundaries: limited, restricted, and arc flash boundary.

Electrical shock hazard: current through the body is the injury mechanism; as little as 50 mA can be lethal, and body resistance drops with wet skin.

An arc flash incident-energy calculation determines the arc rating of PPE; arc-rated clothing is labeled with an arc rating in cal/cm².

Stored energy includes capacitors, springs, hydraulic and pneumatic accumulators, gravity (suspended loads), and thermal energy; all must be dissipated or restrained before work.

Fire tetrahedron: fuel, oxygen, heat, and the chemical chain reaction; removing any one element extinguishes the fire.

Fire classes: A ordinary combustibles, B flammable liquids, C energized electrical, D combustible metals, K cooking oils; extinguisher selection must match the class.

Flammable liquid flash point below 100 °F (37.8 °C); combustible liquid flash point at or above 100 °F; NFPA 30 classifies liquids by flash point and boiling point.

Lower flammable limit (LFL) and upper flammable limit (UFL) bracket the concentration range in air in which a vapor will ignite; below LFL the mixture is too lean, above UFL too rich.

NFPA 101 means of egress components: exit access, exit, and exit discharge; travel distance, dead-end limits, and exit width are set by occupancy classification and occupant load.

Emergency action plan elements (29 CFR 1910.38): reporting procedures, evacuation procedures and routes, accounting for employees, rescue duties, and alarm systems.

Fire prevention plan (29 CFR 1910.39) covers major fire hazards, handling and storage of flammable materials, potential ignition sources, and housekeeping.

Hot work permitting (NFPA 51B) requires a fire watch during and for at least 30 minutes after hot work in areas where combustibles may be present.

Exposure assessment compares the 8-hour time-weighted average (TWA) to the PEL: TWA = (C₁T₁ + C₂T₂ + … + CₙTₙ) / 8 hours, where C is concentration and T is time in hours.

For a ceiling limit, no exposure at any time may exceed the ceiling value; for short-term exposure limits (STEL), the 15-minute average must not exceed the STEL.

The hierarchy of industrial hygiene controls: elimination, substitution, engineering controls (ventilation, enclosure), administrative controls (rotation, scheduling), and PPE.

Local exhaust ventilation captures contaminant at the source; the capture velocity needed depends on the contaminant generation rate and hood geometry.

Respiratory protection requires a written program, medical evaluation, fit testing, and training; a respirator with an assigned protection factor (APF) of 10 reduces exposure tenfold.

Noise: OSHA action level is 85 dBA as an 8-hour TWA; hearing conservation program required at or above that level; PEL is 90 dBA, with a 5 dB exchange rate.

Heat stress controls: acclimatization, work-rest cycles, hydration, and monitoring of wet-bulb globe temperature (WBGT); heat stroke is a medical emergency.

Biological monitoring (for example, blood lead or urinary mercury) assesses absorbed dose and complements air sampling, which assesses external exposure.

Root cause analysis methods: 5 Whys, fishbone (Ishikawa) diagram, fault tree analysis, events and causal factors charting, and barrier analysis.

The 5 Whys technique repeatedly asks why a condition or action occurred until a systemic cause is reached; stopping at human error is a common failure mode.

Fault tree analysis is deductive: it starts with a top event and works backward through AND/OR gates to basic events.

Events and causal factors charting separates the sequence of events from the conditions that allowed them, and identifies the causal factors that, if corrected, would have prevented the incident.

Corrective actions should address the system level (design, procedure, training, supervision, procurement) rather than only the individual; actions are tracked to closure with an owner and due date.

An incident investigation should begin promptly, preserve the scene, and separate fact-finding from fault-finding to encourage honest reporting.

Barrier analysis identifies which preventive and mitigating barriers failed or were missing, and whether the failure was a barrier defect or a barrier bypass.

A corrective action is effective only if verified; verification can include audit, observation, or re-testing after implementation.

OSHA recordable incidence rate = (number of recordable cases × 200,000) / total hours worked; 200,000 is the base for 100 full-time-equivalent workers at 40 hours per week for 50 weeks.

Days away, restricted, or transfer (DART) rate = (DART cases × 200,000) / total hours worked; the severity rate uses days lost per 200,000 hours.

Leading indicators must be valid, actionable, and predictive; simply counting inspections completed without measuring quality of findings is a weak indicator.

Audit types: internal (first-party), supplier (second-party), and certification (third-party); an audit checks conformance to a defined criterion, not just outcomes.

A nonconformity is a failure to meet a requirement; an observation is a finding that does not yet constitute a nonconformity; both are recorded with evidence.

PDCA improvement cycle: plan (identify and plan), do (implement), check (measure and audit), act (standardize or correct).

Benchmarking compares performance against internal history, industry peers, or best-in-class; it does not by itself prove causation.

Statistical process control charts distinguish common-cause variation from special-cause variation; reacting to common-cause variation as if it were special cause increases variation.

OSHA PSM (29 CFR 1910.119) applies to processes involving a listed highly hazardous chemical at or above its threshold quantity, or a flammable liquid or gas at or above 10,000 lb in one location.

PSM has 14 elements: process safety information, process hazard analysis, operating procedures, training, contractors, pre-startup safety review, mechanical integrity, hot work permit, management of change, incident investigation, emergency planning, compliance audits, trade secrets, and employee participation.

Process hazard analysis (PHA) methods: HAZOP, what-if, checklist, failure mode and effects analysis, and fault tree; PHAs must be revalidated at least every five years.

Management of change (MOC) requires review of technical basis, impact on safety and health, modification of procedures, training needs, and authorization before change.

The Globally Harmonized System (GHS) requires safety data sheets in a 16-section format and labels with signal words, hazard statements, and pictograms.

DOT hazard classes: Class 1 explosives, 2 gases, 3 flammable liquids, 4 flammable solids, 5 oxidizers, 6 toxic, 7 radioactive, 8 corrosive, 9 miscellaneous.

Incompatible materials must be segregated; for example, oxidizers are separated from flammables, and acids from bases, to prevent violent reaction.

Dispersion modeling estimates downwind concentration from a release; the consequence depends on release rate, wind speed, atmospheric stability class, and terrain.

ISO 45001 clause 5.4 requires consultation and participation of workers in hazard identification, risk assessment, and incident investigation.

A safety policy must include a commitment to provide safe and healthy working conditions, to satisfy legal requirements, and to continual improvement.

Objectives must be measurable, monitored, and consistent with the policy; they are set at relevant functions and levels.

Competence (clause 7.2) requires determining necessary competence, ensuring persons are competent, and retaining documented evidence.

Outsourcing and contractors must be controlled under clause 8.1.4; the organization retains responsibility for the safety of contractor work.

Emergency preparedness (clause 8.2) requires planned responses, testing of responses, and review after tests or actual events.

Internal audit (clause 9.2) must be planned at intervals and must consider the importance of processes and previous audit results.

Nonconformity and corrective action (clause 10.2) require reaction, evaluation of the need for action, implementation, review of effectiveness, and updating of risks.

OSHA penalties are adjusted annually for inflation; willful and repeated violations carry the highest maximums, and serious violations are assessed per violation.

State-plan states must adopt standards at least as effective as federal OSHA; some states adopt stricter standards, so the applicable rule depends on jurisdiction.

The European Union framework directive 89/391/EEC sets general OSH obligations; individual directives cover specific risks such as noise, vibration, and chemical agents.

ISO 45001 certification is issued by accredited certification bodies; the certification cycle is typically three years with surveillance audits.

29 CFR 1910.132 requires hazard assessment, selection, and training for PPE; 1910.133 covers eye and face protection; 1910.136 covers foot protection.

29 CFR 1910.120 covers hazardous waste operations and emergency response (HAZWOPER); 1910.1200 is the hazard communication standard aligned with GHS.

The OSHA Form 300 log must be posted from February 1 to April 30 each year; severe injury reporting to OSHA is required within 8 hours for a fatality and 24 hours for an in-patient hospitalization, amputation, or loss of an eye.

Consensus standards become legally enforceable through incorporation by reference in a regulation or through adoption in an employer's own policy.

A hazard is not the same as a risk; a hazard exists regardless of exposure, while risk depends on likelihood and severity of harm.

Task-based hazard identification should include non-routine tasks such as maintenance, cleaning, and startup, which often have higher risk than routine production.

Human factors hazard identification looks at error-likely situations: high workload, ambiguous procedures, poor labeling, and inadequate feedback.

Hazard identification should consider the full lifecycle: design, construction, operation, maintenance, decommissioning, and disposal.

Checklist-based identification is fast but limited to hazards already known to the checklist author; it should be supplemented with open-ended methods.

A hazard register is a living document that records identified hazards, associated risk ratings, controls, and responsible owners.

Energy source identification during hazard analysis must include stored energy, not just the primary supply; this feeds directly into LOTO procedures.

Health hazards are often missed in safety-focused identification; include chemical, physical, biological, and ergonomic stressors in the analysis.

Qualitative risk assessment uses descriptive categories; semi-quantitative uses numeric scales; quantitative uses measured frequencies and consequences.

Risk matrices can produce risk-ranking inconsistencies; two hazards with the same score may have very different actual risk, so high-severity/low-likelihood hazards need separate scrutiny.

ALARP demonstration requires showing that the cost of further reduction is grossly disproportionate to the benefit, not merely that some controls exist.

Tolerability limits vary by jurisdiction; the UK HSE uses a framework where individual risk above 1×10⁻³ per year is intolerable and below 1×10⁻⁶ per year is broadly acceptable.

Risk treatment must be recorded with the rationale, the responsible person, and the target completion date, and the residual risk must be re-evaluated.

Hierarchy of controls is applied at the risk-treatment stage; PPE is a last resort and should not be the only control for a high-severity hazard.

Dynamic risk assessment is used in changing conditions where pre-assessment is not possible; it requires competence and clear stop-work authority.

Risk communication must be understandable to the affected workers; technical risk numbers alone do not support informed decisions.

The NIOSH lifting equation multipliers: HM = 25/H (H in cm, minimum 25 cm), VM = 1 − 0.003|V − 75|, DM = 0.82 + 4.5/D, AM = 1 − 0.0032|A|, and FM and CM come from tables.

The NIOSH equation assumes the load is held with two hands, the lifting is smooth, and the worker is physically capable; it does not apply to one-handed lifting or carrying.

The revised NIOSH equation's frequency multiplier depends on lifts per minute, duration, and recovery time; higher frequency reduces the RWL.

The ACGIH hand-activity level (HAL) is used with the vibration TLV; exposure points accumulate over a workday.

Cognitive workload can be assessed with the NASA-TLX, which rates mental, physical, temporal, performance, effort, and frustration demands.

Human error rates are higher for tasks requiring sustained vigilance and for tasks with ambiguous feedback; design should provide clear, immediate feedback.

Anthropometric data should be matched to the population actually using the equipment; military or general-population data may not match a specific workforce.

Participatory ergonomics engages workers in identifying and solving ergonomic problems, which improves the fit of solutions to actual work.

Guard types: fixed, interlocked, adjustable, self-adjusting, and presence-sensing; the choice depends on the frequency of access and the nature of the hazard.

A fixed guard is preferred where access is infrequent; an interlocked guard is used where access is needed for operation or maintenance.

Interlocks must be designed so that a single fault cannot defeat them; a simple switch that can be bypassed with tape is not adequate.

The ANSI B11.19 safety distance formula uses the approach speed and the total stopping time of the machine and safeguarding device.

Presence-sensing devices must be positioned so the operator cannot reach the hazard before the machine stops; they do not protect against reaching around or over the detection zone.

Guards must be robust enough to withstand expected impact and must not be easily removable without a tool.

Machine guarding training must cover the purpose of guards, the hazards they control, and the prohibition on defeating them.

Guards should be inspected at the start of each shift and after any maintenance or adjustment.

The LOTO written program must include procedures for each machine or equipment, training for authorized and affected employees, and periodic inspection at least annually.

Periodic inspection of LOTO must be performed by an authorized employee other than the one using the procedure, and must correct any deviations found.

Affected employees are those whose work requires them to operate or work near equipment being serviced; they must be notified and trained on the prohibition against removing locks.

Tagout devices must be standardized, durable, and indicate the identity of the person applying the tag and the reason for the lockout.

Electrical safety-related work practices under 1910.333 require de-energizing and testing before work; live work requires justification and PPE.

The arc flash boundary is the distance at which incident energy equals 1.2 cal/cm², the threshold for a second-degree burn.

Approach boundaries: the limited approach boundary is where a shock hazard exists for unqualified persons; the restricted approach boundary requires qualified persons and shock protection.

Ground fault circuit interrupters (GFCIs) protect against ground faults by sensing current imbalance; 1910.304 requires GFCI protection in construction and certain wet locations.

Fire extinguisher types: water (A), foam (A, B), carbon dioxide (B, C), dry chemical (A, B, C), and wet chemical (K); the label must match the hazard.

Extinguisher inspection: monthly visual inspection and annual maintenance; hydrostatic testing intervals depend on extinguisher type.

Sprinkler systems: wet-pipe, dry-pipe, pre-action, and deluge; the choice depends on freeze risk and the speed of response needed.

Means of egress must be continuous and unobstructed; exit doors must be openable from the inside without a key or special knowledge.

Occupant load determines exit width and the number of exits; the required number of exits increases with occupant load and travel distance.

Emergency evacuation drills must be conducted at intervals; the frequency depends on the occupancy type and jurisdiction.

Fire alarm initiation devices include manual pull stations, smoke detectors, heat detectors, and sprinkler flow switches.

The fire triangle and tetrahedron explain the four elements; the tetrahedron adds the chemical chain reaction, which is interrupted by clean agents.

Personal air sampling uses a pump and a collection medium; the result is reported as a concentration and compared to the applicable limit.

Direct-reading instruments provide immediate results for gases and vapors, but they may not be specific; confirmatory sampling is often needed.

The OSHA PEL for noise is 90 dBA as an 8-hour TWA; the exchange rate is 5 dB, so 95 dBA is allowed for 4 hours.

Hearing protector attenuation is estimated with the noise reduction rating (NRR); the effective protection is often calculated with a derating factor.

Heat stress assessment uses WBGT and metabolic rate to determine work-rest cycles; acclimatization takes about 5–7 days of gradual exposure.

Chemical exposure control should follow the hierarchy; local exhaust ventilation is often the most effective engineering control for vapors and dusts.

Biological monitoring results must be interpreted with knowledge of the substance's half-life and the timing of exposure.

Occupational health surveillance includes medical examinations and biological monitoring for workers exposed to specific hazards such as lead, silica, or noise.

The investigation should establish what happened, how it happened, and why it happened; the why is the root cause.

Human error is a symptom, not a root cause; the analysis must identify the conditions that made the error likely.

The fishbone diagram organizes causes into categories: people, methods, machines, materials, measurement, and environment.

Fault tree analysis uses Boolean logic; an AND gate means all basic events must occur, an OR gate means any one can cause the top event.

Corrective actions should be specific, measurable, assigned to an owner, and tracked to completion.

Investigation reports should include a timeline, the sequence of events, causal factors, and recommendations.

Lessons learned should be shared across the organization to prevent recurrence elsewhere.

A near-miss investigation uses the same methods as an injury investigation and often reveals higher-value corrective actions.

The total recordable case rate and DART rate are lagging indicators; they reflect outcomes after the fact and do not predict future performance.

Leading indicators should be linked to the most significant risks; a generic indicator may not reflect the organization's actual hazard profile.

Audit findings should be graded by risk; a major nonconformity requires immediate action, while a minor one can be scheduled.

Audit evidence must be verifiable; interviews, observations, and document reviews are the standard evidence types.

Corrective action from audits should be tracked in the same system as incident corrective actions to avoid duplication and gaps.

Management review should use trend data, not just the latest period, to detect drift.

Continuous improvement requires a feedback loop from measurement to action and back to measurement.

Benchmarking should compare like with like; differences in reporting thresholds and industry mix can make raw rates misleading.

The PSM threshold for a flammable liquid or gas is 10,000 lb in one location; for listed highly hazardous chemicals, the threshold is specified in Appendix A.

Process safety information includes chemical data, technology data, and equipment data; it is the basis for the process hazard analysis.

Mechanical integrity covers pressure vessels, storage tanks, piping, relief devices, and controls; inspection and testing must follow recognized codes.

Pre-startup safety review confirms that construction is complete, procedures are in place, training is done, and the PHA recommendations are resolved.

Hot work permits must be issued before hot work in a PSM-covered process and must include fire watch and gas testing.

Management of change must be documented and must consider the impact on safety, health, and the environment.

Compliance audits under PSM must be conducted at least every three years.

Emergency planning must include evacuation routes, alarm systems, and coordination with local responders.

The PDCA cycle in ISO 45001 maps to clauses 6 (plan), 7 and 8 (do), 9 (check), and 10 (act).

Top management must demonstrate leadership by establishing policy, ensuring resources, and integrating the SMS into business processes.

Worker participation is a requirement, not a suggestion; workers must be consulted on hazard identification and risk assessment.

The organization must determine the legal and other requirements applicable to its hazards and evaluate compliance.

Objectives must be consistent with the policy and must be measurable and monitored.

Competence includes training, experience, and qualification; records must be retained.

Communication must cover internal and external parties, including contractors and visitors.

The SMS must be reviewed at planned intervals and updated to reflect changes in the organization and its context.

OSHA standards are published in Title 29 of the Code of Federal Regulations; the general industry part is 1910.

The General Duty Clause requires employers to provide a workplace free from recognized hazards likely to cause death or serious physical harm.

Recordkeeping criteria for a recordable injury include medical treatment beyond first aid, loss of consciousness, days away from work, or restricted work.

The OSHA 300A summary must be posted from February 1 to April 30.

Severe injury reporting: fatalities within 8 hours; in-patient hospitalization, amputation, or loss of an eye within 24 hours.

State-plan states may have stricter requirements; the employer must comply with the applicable state plan.

Consensus standards such as ANSI/ASSP and NFPA are not law unless incorporated by reference or adopted by the employer.

ISO 45001 certification requires an accredited certification body and a three-year surveillance cycle.

Hazard identification should cover routine and non-routine activities, including maintenance and emergency situations.

The JHA breaks a task into steps and identifies hazards and controls for each step.

HAZOP uses guide words applied to process parameters to find deviations from design intent.

FMEA ranks failure modes by severity, occurrence, and detection to prioritize action.

What-if analysis asks open-ended questions about potential deviations and their consequences.

Near-miss reporting is a leading indicator and a source of hazard information.

Change analysis identifies hazards introduced by changes in process, equipment, or personnel.

The hazard register records identified hazards, risk ratings, controls, and owners.

Risk = likelihood × severity; the matrix size determines the granularity of the rating.

ALARP requires demonstrating that further risk reduction is grossly disproportionate to the benefit.

Risk treatment options: avoid, reduce likelihood, reduce severity, transfer, and accept.

Bow-tie analysis links threats and preventive barriers to consequences and mitigating barriers.

LOPA estimates the risk reduction of independent protection layers.

Residual risk must be re-evaluated after controls are applied.

Risk acceptance criteria should be defined before the assessment.

High-severity, low-likelihood hazards need separate scrutiny because matrix scores can understate them.

NIOSH RWL = LC × HM × VM × DM × AM × FM × CM; LI = load / RWL.

LC = 23 kg (51 lb); the equation applies to two-handed, smooth lifting.

Design for the 5th percentile for reach and the 95th percentile for clearance.

Repetitive motion risk factors include repetition, force, posture, vibration, and recovery time.

The ACGIH HAL and vibration TLV are used to evaluate hand-arm vibration.

Cognitive workload can be assessed with NASA-TLX.

Control-display compatibility improves performance and reduces error.

Participatory ergonomics engages workers in identifying and solving problems.

29 CFR 1910.212(a)(1) requires guarding of point of operation, nip points, rotating parts, flying chips, and sparks.

Fixed guards are preferred where access is infrequent; interlocked guards are used where access is needed.

Interlocks must be designed so a single fault cannot defeat them.

Safety distance D = K × T, where K is approach speed and T is total stopping time.

Two-hand controls require both hands on controls during the hazardous portion of the cycle.

Guards must not create new hazards such as sharp edges or pinch points.

Guard openings must be sized to exclude the body part they are meant to exclude.

Defeated or removed guards are among the most frequently cited violations.

29 CFR 1910.147 applies to servicing and maintenance where unexpected energization could injure.

The six-step LOTO sequence: notify, shut down, isolate, lock and tag, release stored energy, verify.

Each authorized employee applies a personal lock; group lockout uses a hasp or lockout device.

Tagout alone is permitted only when the device cannot be locked out and equivalent protection is demonstrated.

NFPA 70E establishes arc flash and shock risk assessment and approach boundaries.

Current through the body is the shock injury mechanism; as little as 50 mA can be lethal.

Arc-rated clothing is labeled with an arc rating in cal/cm².

Stored energy includes capacitors, springs, accumulators, gravity, and thermal energy.

Fire tetrahedron: fuel, oxygen, heat, and chemical chain reaction.

Fire classes: A, B, C, D, and K; extinguisher selection must match the class.

Flammable liquid flash point below 100 °F; combustible liquid at or above 100 °F.

LFL and UFL bracket the flammable concentration range in air.

NFPA 101 means of egress: exit access, exit, and exit discharge.

Emergency action plan elements include reporting, evacuation, accounting for employees, and alarms.

Hot work permitting requires a fire watch during and for at least 30 minutes after hot work.

Exit doors must be openable from the inside without a key or special knowledge.