Industrial Hygiene: Physical and Ergonomic Hazards
Include excessive levels of ionizing and nonionizing electromagnetic radiation, noise, vibration, illumination, and temperature.
In occupations where there is exposure to ionizing radiation (as in x-raying pipe), time, distance, and shielding are important tools in ensuring worker safety. Danger from radiation increases with the amount of time one is exposed to it; hence, the shorter the time of exposure the smaller the radiation danger. Distance also is a valuable tool in controlling exposure to both ionizing and non-ionizing radiation. Radiation declines the further away from the source that you are. The rate that it diminishes is the inverse of the square of the distance (if you double the distance, the exposure will be one fourth as strong. If you triple the distance, the exposure will be one ninth as strong). Shielding also is a way to protect against radiation. The greater the protective mass between a radioactive source and the worker, the lower the radiation exposure.
Nonionizing radiation, like heat and light, is also dealt with by shielding workers from the source. Sometimes limiting exposure times to nonionizing radiation or increasing the distance is not effective. Laser radiation, for example, cannot be controlled effectively by imposing time limits. An exposure can be hazardous that is faster than the blinking of an eye. Increasing the distance from a laser source may require miles before the energy level reaches a point where the exposure would not be harmful.
Noise, another significant physical hazard, can be controlled by various measures. Noise can be reduced by implementing engineering, work practice, and administrative controls. When noise levels are at or exceed 85 dBA, hearing protection must be used.
Another physical hazard, radiant heat exposure from the sun or in factories such as steel mills, can be controlled by installing reflective shields and by providing protective clothing.
The science of ergonomics studies evaluates a full range of tasks including, but not limited to, lifting, holding, pushing, walking, and reaching. Many ergonomic problems result from increased repetition and from poorly designed job tasks. Additionally hazards such as excessive vibration and noise, eye strain, repetitive motion, and heavy lifting cause ergonomic problems. Improperly designed tools can be ergonomic hazards. Repetitive motions or repeated shocks over prolonged periods of time can often cause irritation and inflammation of the tendon sheath of the hands and arms, a condition known as carpal tunnel syndrome. Ergonomic hazards are avoided primarily by the effective design of a job or jobsite and better designed tools or equipment that meet workers’ needs in terms of physical environment and job tasks. More information on this subject has been covered in the November, 2008 series of Tool box Talks covering Lifting, Repetitive Tasks, Excessive Force, Material Handling, Tools and the J.J. White, Inc. Stretch and Flex Program.