How each hazard normally turns into an injury

Fire needs three things at once, heat, fuel, and oxygen, the fire triangle. Instructional and extinguisher-class material adds a fourth face, an uninhibited chain reaction, giving the fire tetrahedron. Removing any one face stops the fire: water or foam removes heat, smothering removes oxygen, moving fuel removes fuel, and a dry-chemical agent interrupts the chain reaction directly. A bench fire hazard is anything that stacks two or three of these faces close together, a frayed cord (heat) near a solvent-soaked wipe (fuel) in open air (oxygen).

Electrical shock and ignition follow a similar logic to fire's heat face. Damaged insulation, a missing ground pin, an overloaded circuit, or a wet surface each raise the chance that current takes a path through a person or ignites nearby material instead of staying inside the equipment. Walking surfaces kept clean and dry, equipment kept free of recognized damage, and circuits kept within their rated load are the routine controls, per OSHA's general-industry electrical rules at 1910.303 through 1910.305 and its walking-working-surfaces rule at 1910.22.

Sharps and broken glass injure by direct contact with a point or edge, so the model is exposure distance, not force: a safety-engineered device, a blade holder, forceps, or tongs keeps the sharp edge away from bare or gloved skin at every step from use to disposal, per OSHA's Bloodborne Pathogens standard at 1910.1030.

Ergonomic injury builds differently, over time rather than in one event. NIOSH names repetition, force, and awkward or static posture as the core musculoskeletal-disorder risk factors, and its hierarchy of controls for reducing them runs, in order: reduce or eliminate the repetitive exposure first, then apply engineering controls such as adjustable equipment, then administrative controls such as task rotation and breaks, then training, with posture coaching alone treated as the weakest control rather than the primary one.

Falls and slips follow height and surface condition: an unprotected edge four feet or more above a lower level requires fall protection under OSHA 1910.28, and a wet, cluttered, or improperly climbed surface is a slip or fall waiting on a person to cross it, per OSHA's walking-working-surfaces and ladder rules at 1910.22 and 1910.23.

Every physical hazard on this list becomes an injury only when its full set of conditions lines up in one place at one time, so a control that removes even one condition, oxygen, current path, exposure distance, repetition, or a wet surface, breaks the chain before it reaches a person.