Bioenvironmental Engineering Apprentice Block IV: Chemical Controls PDF

Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 1: Control Options BLOCK IV - UNIT 1: CONTROL OPTIONS Objective 1a: List chemical threat control options. Chemicals can be safely stored, handled, and used if the hazards are fully understood and the necessary h...

Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 1: Control Options BLOCK IV - UNIT 1: CONTROL OPTIONS Objective 1a: List chemical threat control options. Chemicals can be safely stored, handled, and used if the hazards are fully understood and the necessary hazard controls are in place. The objective of chemical controls is to ensure that exposure to harmful chemicals does not result in occupational illness. The type of control measures instituted depend on the nature of the hazard and its routes of entry into the body. HIERARCHY OF CONTROLS A hierarchy of controls is used as a means of determining how to implement feasible and effective control solutions. It ranks control measures in the order of their effectiveness and stresses the elimination of the hazards as preferable to the use of personal protective equipment (PPE). The methods of control of health hazards in the workplace are divided into three categories: Engineering, Administrative and PPE. The Figure 1 is a representation of the hierarchy of controls: Figure 1: Hierarchy of Controls The control methods at the top are preferred over those at the bottom because they do not rely on the worker to be effective. Following this hierarchy normally leads to the implementation of safer processes, where the risk of overexposure has been substantially reduced. 6 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 1: Control Options ENGINEERING CONTROLS Engineering controls are favored over administrative controls and PPE because they remove the hazard before it becomes in contact with the worker. Well-designed engineering controls can be highly effective in protecting workers and will typically not be dependent on worker interactions to achieve a high level of protection. SUBSTITUTION Substitution refers to the replacement of a hazardous material or activity with one that is less hazardous (e.g., the replacement of mercury thermometers with alcohol thermometers or dip coating materials rather than spray coating to reduce the inhalation hazard). MINIMIZATION Minimization is the expression used when a hazard is lessened by scaling down the hazardous process. Hence, the quantity of hazardous materials used and stored is reduced, lessening the potential hazards. ISOLATION Isolation is the term applied when a barrier is interposed between a material, equipment, or process hazard and the property or persons who might be affected by the hazard (e.g., glove box, blast shield). VENTILATION Ventilation is a method of controlling the work environment by strategically supplying (adding) or exhausting (removing) air. The two types of ventilation are local exhaust and general or dilution ventilation. Local exhaust systems are designed to catch the contaminated air at or near the source and remove it from the area before it reaches the workers breathing zone. General or dilution ventilation attempts to control hazardous atmospheres by diluting the atmosphere to a safe level by either exhausting or supplying air to the area. ADMINISTRATIVE CONTROLS Administrative controls are frequently used with existing processes where hazards are not particularly well controlled. They consist of managerial efforts to reduce hazards through planning, training, job rotation, reduction of exposure time and written policies and procedures. These methods for protecting workers have proven to be less effective than engineering controls, requiring significant effort by the affected workers. 7 Bioenvironmental Engineering Apprentice Block IV: Chemical Controls B3ABY4B031-0A1B Unit 1: Control Options PERSONAL PROTECTIVE EQUIPMENT (PPE) When engineering and administrative controls cannot adequately control chemical hazards, PPE must be considered. PPE includes a wide variety of items worn by a worker to isolate them from chemical hazards. PPE is considered the last resort of protection, creating a physical barrier at the point of exposure. It includes articles to protect the eyes, skin, and the respiratory system (e.g., goggles, face shields, coats, gloves, aprons, respirators). The effectiveness of PPE is highly dependent on the user. Some items of PPE may be perceived as cumbersome and uncomfortable to wear so workers may resist using it or use it improperly. 8