A. Engineering controls
Engineering controls are the primary means of controlling exposure to hazardous chemicals. Local ventilation, including fume hoods, biosafety cabinets, glove boxes, vented storage cabinets, and vented canopies are the most common types of engineering controls. Upon request, the Chemical Hygiene Officer provides assistance in determining the appropriate type of engineering controls for specific operations.
Improper function of engineering controls must be reported to the Chemical Hygiene Officer immediately; systems shall be taken out of service until proper repairs have been performed. No modification of engineering controls may occur unless testing indicates that worker protection will continue to be adequate.
The following work practices shall apply to the use of fume hoods:
- Confirm adequate fume hood ventilation performance prior to opening chemical containers inside the fume hood.
- Minimize the storage of chemicals and equipment inside the fume hood.
- Minimize foot traffic and other forms of potential air disturbances near the face of the fume hood.
- Keep the sash closed when the fume hood is not in use.
- Do not allow sources of ignition inside the fume hood when flammable liquids or gasses are present.
- Fume hood face velocities shall be maintained between 90 and 110 feet per minute. A record of each inspection shall be maintained by the Chemical Hygiene Officer.
B. Personal Protective Equipment
Protective equipment including gloves, face shields, safety glasses, safety goggles, lab coats and aprons are used to supplement engineering controls or when engineering controls are not sufficient to adequately control exposure. This equipment does not eliminate the hazard, protects only the wearer, and does not protect anyone else. Personal protective equipment must be carefully selected to ensure that it is compatible with the chemicals used.
- Eye Protection
- The use of proper eye protection is essential for everyone who enters a chemical work area. Eye protection must be made available to all employees or visitors to laboratories where chemicals are used or stored. Laboratory supervisors must establish the level of eye protection needed per laboratory activity.
- In the Chemistry Department, safety glasses meeting ANSI Z87.1 are the minimum eye protection required for employees and students, and shall be worn at all times when in the laboratory.
- Chemical splash goggles offer the best eye protection from splashes. Chemical splash goggles and/or a full face shield should be worn when working with large volumes of corrosives (e.g., > 1L) and for other handling operations where splash hazards exist.
- Face shields protect the face and neck from flying particles and splashes. A face shield and cryogenic gloves shall be worn when dispensing liquid nitrogen from a pressurized vessel.
- Protective Clothing
- when the possibility of chemical contamination exists, protective clothing that resists physical and chemical hazards should be worn over street clothes. Lab coats are appropriate for minor chemical splashes and spills, whereas plastic or rubber aprons provide the best protection from corrosive or irritating liquids. Excessively loose clothing, shorts, open-toed or perforated shoes, and unrestrained hair may pose hazards in the laboratory.
- Protective gloves should be worn when handling hazardous chemicals and very hot or very cold materials. Inspect all gloves for signs of degradation or puncture before use. Change disposable gloves when there is any sign of contamination.
- Disposable nitrile gloves offer protection from incidental splashes or contact with many laboratory chemicals and are appropriate under most circumstances. When working with particularly hazardous substances, corrosives in high concentrations, handling chemicals for extended periods of time, or immersing all or part of a hand into a chemical, the appropriate glove materials should be selected based on chemical compatibility. See Appendix A for a glove selection guide or consult the MSDS.
- A respirator may only be used when engineering controls, such as general ventilation or a fume hood, are not feasible or do not reduce the exposure of a chemical to acceptable levels. Any worker who believes that respirator protection is needed must contact the Chemical Hygiene Officer for evaluation of the hazard. For more information on respirator use, contact the Chemical Hygiene Officer.
C. Administrative Controls
It may be necessary to supplement engineering controls and protective equipment with administrative controls, such as restricting access to an area, restricting use of particular chemicals to a limited group of people, or limiting the length of exposure.