Workplace exposure engineering controls

Within this guidance the term occupational exposure limit(s) refers to limits in the air of the workplace or biological limit values. In addition, for the purposes of this document exposure control means the full range of specific protection and prevention measures to be taken during use in order to minimize worker and environmental exposure. Engineering control measures that are needed to minimize exposure to, and risks associated with the hazards of, the substance or mixture should be included in this section. 

When the potential hazard cannot be removed, replaced, or enclosed, the next best approach is a barrier to exposure or, in the case of air contaminants, local exhaust ventilation to remove the contaminant from the workplace. This engineered control involves potential exposure to the worker even in normal operations. Consequently, it should be used only in conjunction with other types of controls, such as safe work practices designed specifically for the site condition and/or PPE. Examples include ... 

Sources of human exposure to formaldehyde are engine exhaust, tobacco smoke, natural gas, fossil fuels, waste incineration, and oil refineries (129). It is found as a natural component in fmits, vegetables, meats, and fish and is a normal body metaboHte (130,131). FaciUties that manufacture or consume formaldehyde must control workers exposure in accordance with the following workplace exposure limits in ppm action level, 0.5 TWA, 0.75 STEL, 2 (132). In other environments such as residences, offices, and schools, levels may reach 0.1 ppm HCHO due to use of particle board and urea—formaldehyde foam insulation in constmction. 

Action Levels. The scheme requires that the exposures of one or more potentially-exposed workers be monitored periodically. If all of the air concentrations measured are below the "action level (AL), which is of the "permissible exposure limit" (PEL), then no further action is required unless the process is changed. The workplace is deemed to be in compliance with the standard. If a value exceeds the PEL, the workplace is declared to be out of compliance and some form of remedial action is required, e.g., a process change, engineering controls or personal protective equipment. Finally, if the sample value is between the AL and the PEL further sampling is required until two values in a row are observed below the AL (workplace in compliance) or one value is observed above the PEL (workplace out of compliance). 

OSHA requires employers of workers who are occupationally exposed to benzene to institute engineering controls and work practices to reduce and maintain employee exposure at or below permissible exposure limits (PEL). If the employer can document that benzene is used in the workplace less than 30 days per year, the employer can use any combination of engineering controls, work practice controls, or respirators to reduce employee exposure to or below the (PEL) of 1 ppm. However, the employer must use... 

In 1996, there were 25,000 workers employed in 75-100 domestic wood treatment plants using coal tar creosote. As a result of the use of engineering controls and personal protective equipment (e.g., respiratory protection and impervious gloves) required in the 1986 settlement of the EPA Special Review process,1 airborne exposures to creosote components in the workplace are generally below the OSHA permissible exposure limit (PEL) of 0.2 mg benzene soluble particulates perm3 air (Rivers 1990). 

In May 1978, OSHA and NIOSH jointly published Current Intelligence Bulletin (CIB) 26 NIAX Catalyst ESN. In this CIB, OSHA and NIOSH recommended that occupational exposure to NIAX Catalyst ESN, its components, dimethylaminopropionitrile and bis(2-(dimethylamino)ethyl)ether, as well as formulations containing either component, be minimized. Exposures should be limited to as few workers as possible, while minimizing workplace exposure concentrations with effective work practices and engineering controls. Exposed workers should be carefully monitored for potential disorders of the nervous and genitourinary system. Although substitution is a possible control measure, alternatives to NIAX Catalyst ESN or its components should be earefully evaluated with regard to possible adverse health effeets. 

Technical exposure control. Additional necessary exposure control measures which are not noted in heading 7 have to be noted. The described measures are important for the risk assessment in the workplace, and these have to be done by the employer in accordance with Article 4 of Directive 98/24/EC [4-15]. The design of appropriate work processes and engineering controls, the use of adequate equipment and materials, and the application of collective protection measures at source are required. 

This chapter discusses the requirements for personal protective equipment (PPE). It also addresses other control mechanisms and procedures. Engineering controls should be the primary method used to eliminate or minimize hazard exposure in the workplace. Administrative controls must be set in motion prior to the use of PPE. When such controls are not practical or applicable, PPE shall be employed to reduce or eliminate personnel exposure to hazards. PPE will be provided, used, and maintained when it has been determined that its use is required and that such use will lessen the likelihood of occupational injuries and/or illnesses. All personal protective clothing and equipment should be of a safe design and appropriate for the work to be performed. Only those items of protective clothing and equipment that meet National Institute for Occupational Safety and Health (NIOSH) or American National Standards Institute (ANSI) standards are to be procured or accepted for use. 

Recent regulatory requirements make hazard analysis part of the PPE selection process. Hazard analysis procedures should be used to assess the workplace to determine if hazards are present, or are likely to be present, which may necessitate the use of PPE. As part of this assessment, the employees work environment should be examined for potential hazards that are likely to present a danger to any part of their bodies. If it is not possible to eliminate workers exposure or potential exposure to the hazard through the efforts of engineering controls, work practices, and administrative controls, then the proper PPE must be selected, issued, and worn. The checklist found in Figure 24.3 may be of assistance in conducting a hazard analysis. 

As with other types of hazards, the employer must implement feasible engineering controls and work practices before resorting to PPE such as earplugs or earmuffs. If engineering and work practice controls do not lower employee exposure to workplace noise to acceptable levels, then employees must be provided with appropriate PPE. 

When hazardous workplace exposures cannot be controlled by these measures, personal protective equipment (PPE) becomes necessary." While the goal of safety officials is certainly to engineer out all workplace hazards, we realize that this goal is virtually impossible to achieve. Even in this day of robotics, computers, and other automated equipment and processes, the... 

Engineering controls reduce employee exposure in the workplace by either removing the hazard or isolating the worker from exposure. Self-sheathing needles and special containers for contaminated sharp instruments are examples of engineering controls. Engineering controls must be examined and maintained or replaced on a scheduled basis. 

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