Control Measures and Equipment

Chemical safety is achieved by continual awareness of chemical hazards and by keeping the chemical under control by using precautions, including engineering safeguards such as hoods. Faculty, students, and staff should be familiar with the precautions to be taken, including the use of engineering and other safeguards. Laboratory supervisors should be alert to detect the malfunction of engineering and other safeguards. All engineering safeguards and controls must be properly maintained and inspected on a regular basis, and not overloaded beyond their design limits.

Ventilation (Hoods)

  • Always work in a hood when working with toxic chemicals that have low air concentration limits or that have high vapor pressures.
  • Fume hoods should provide 100 linear feet per minute of air flow.
  • There should be a label on each hood verifying that the airflow has been checked within the last six months. If there is any doubt that a hood is working properly call the Science Center Office (x3136) and mark on the hood "Out of Order".
  • Laboratory personnel should understand and comply with:
    • A fume hood is a safety backup for condensers, traps, or other devices that collect vapors and fumes. It is not used to "dispose" of chemicals by evaporation.
    • The apparatus inside the hood should be placed on the floor of the hood at least six inches away from the front edge. Large apparatus should be placed on "legs" at least two inches off the work surface to allow for adequate airflow through the hood. In the event of hood failure, personnel should remove materials if necessary and consult the Laboratory Supervisor for any other steps to be taken.
    • Fume hood sashes should be lowered at all times except when necessary to open them to adjust the apparatus that is inside the hood.
    • The hood interior should never be used as a storage area for chemicals, apparatus, or other materials. This can adversely effect the hood's ability to contain toxic gases or vapors.

Flammable Liquid Storage

  • Large volumes of flammable liquids in the stockroom (one gallon size) should be stored in an approved flammable liquid storage cabinet or in the chemical storage room in the stockroom. All flammable materials should be ordered in plastic coated bottles when available.
  • Large volumes in individual laboratories should be stored in secondary containers in approved cabinets under the hood.
  • For safety and to minimize disposal costs, order the smallest practical amounts of hazardous chemicals.

Eye Wash Fountains and Safety Showers

  • All laboratories must have quick and easy access to safety showers and eyewashes. Be sure that access to eyewashes and safety showers is not restricted or blocked by storage objects.
  • Personnel in the laboratory must be aware of the location of these devices.
  • The functioning of eyewash fountains and safety showers are verified periodically by Physical Plant or the Chemical Hygiene Officer. Promptly report any unit that is not functioning properly to the Science Center Office (x3136) for repair.

Personal Protective Equipment

If personal protective equipment is required, it is included in the Standard Operating Procedure for that chemical. The type and level of equipment can be determined with the aid of the Chemical Hygiene Officer. Any use of personal protection equipment should only be considered after the options of reducing the hazards by engineering controls such as the use of hoods or experimental design are reviewed and implemented where possible.


If there is a need to wear a respirator, the following procedures must be followed:

  • Obtain a medical approval form from Metrowest Medical Center-Natick Campus or your personal physician and submit it to the Chemical Hygiene Officer. Completed forms are filed in the Science Center Office.
  • The Chemical Hygiene Officer will arrange for the proper selection, fit testing, and training before use of a respirator can begin. (This will take some advance time to schedule. The actual time to complete the requirements is less than 30 minutes.)
  • There will be an annual review of respirator use.

Eye Protection

The use of eye protection shall be determined by the laboratory supervisor and the Chemical Hygiene Officer.

Protective Clothing

The use of protective clothing, including gloves, shall be determined by the laboratory supervisor and the Chemical Hygiene Officer.

  • The Standard Operating Procedure for a particular chemical shall include whether protective clothing is required. Standard Operating Procedures
  • Protective clothing shall be chosen, with the aid of the Chemical Hygiene Officer.
  • Contaminated protective clothing shall be decontaminated if possible or disposed of properly. This includes packaging the clothing in containers or bags and calling the Chemical Hygiene Officer for assistance.
  • Open-toed shoes or sandals should not be worn in laboratories.
  • Contaminated lab coats should not be worn.


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