8.4 Physical Hazards, Hearing Conservation, Radiation, Heat, and Vibration

Health Hazards Beyond Chemicals

Industrial hygiene includes physical hazards as well as chemical and biological hazards. Physical hazards arise from energy or environmental conditions: noise, vibration, heat, cold, radiation, pressure, lighting, and sometimes ergonomic stressors. The ASP blueprint specifically includes hearing conservation, physical hazards, radiation, and related occupational health topics.

Noise is a major physical hazard because excessive exposure can cause permanent hearing loss and can interfere with communication and warning signals. A hearing conservation program usually begins with identifying noisy tasks, measuring exposure, and determining who is included. Controls may include quieter equipment, maintenance, isolation, enclosures, barriers, damping, administrative scheduling, and hearing protection.

Hearing protection must be selected and used correctly. Earplugs or earmuffs that are not fitted, worn consistently, or suitable for the noise spectrum may not provide expected protection. Training should cover why protection is needed, how to insert or wear it, how to maintain it, and when to replace it. Audiometric follow-up can help detect shifts and evaluate whether the program is working.

Physical Hazard Control Themes

Radiation can be ionizing or non-ionizing. Ionizing radiation has enough energy to remove electrons from atoms and requires strong controls for sources, dose, shielding, time, distance, and access. Non-ionizing radiation includes sources such as lasers, radiofrequency energy, ultraviolet radiation, and infrared energy. The control approach depends on the source, energy, exposure pathway, and affected tissue.

The time, distance, and shielding principle is useful for many radiation scenarios. Reduce time near the source, increase distance when possible, and use shielding appropriate for the radiation type. Administrative controls, warning signs, interlocks, source security, training, and monitoring may also be needed. The safety professional should involve qualified radiation expertise for complex sources.

Heat stress depends on temperature, humidity, radiant heat, workload, clothing, acclimatization, hydration, medications, health status, and work-rest patterns. Controls can include scheduling, shade, ventilation, cooling, rest breaks, hydration, buddy checks, acclimatization, and emergency response for symptoms. Cold stress has different concerns: wind, wet clothing, contact with cold surfaces, fatigue, and reduced dexterity.

Vibration can affect hands and arms when using tools or the whole body when operating vehicles or heavy equipment. Controls include selecting lower-vibration tools, maintaining equipment, using damping materials, limiting duration, improving seating, reducing rough travel surfaces, and reporting symptoms early. Gloves may help with comfort, but they are not a complete vibration control strategy.

ASP questions may ask for the best program-level control. Prefer source reduction and engineering controls when feasible, then administrative controls and protective equipment. Also look for medical or occupational health follow-up when exposure can produce progressive effects, such as hearing loss or heat illness susceptibility.