Chemicals in the Classroom

Before starting any laboratory activity, be sure to complete a hazard analysis and risk assessment. If possible, consider replacing chemicals with less-hazardous substances, or conduct a safer experiment that can demonstrate the same learning objective.

Chemical Handling

• Always wear proper personal protective equipment (PPE) for each experiment, including approved eye protection, lab coats or aprons, and appropriate gloves.
  
  
• Check each label carefully to verify chemical identity before use.
  
  
• For dry chemicals, remove only the amount needed and never return excess to the original container. Dispose of excess properly.
  
  
• Use a spatula or scoopula to remove solid reagents. Avoid using metal spatulas when working with peroxides to prevent explosions.
  
  
• To dilute acids, always add acid to water slowly while stirring in a heat-resistant container. Never add water to concentrated acid.
  
  
• Use a hot-water bath to heat or evaporate flammable liquids; never use an open flame directly.
  
  
• Always remove gloves and wash hands before handling any personal item or before leaving the lab. Do not touch doorknobs, handles, water fountains, water faucets, or anything else that might expose someone to the chemicals on gloves.
  
  
• Respond to and clean up spills promptly and according to protocol.

Fume Hood Operation

• Fume hoods must be professionally installed, certified, and tested annually (California Code of Regulations, Title 8, Section 5154.1).
  
  
• Use fume hoods whenever toxic vapors, dust, or gases may be generated. Keep the sash as low as possible during operation for optimal protection and efficiency.
  
  
• Keep your head and body outside the hood at all times.
  
  
• Never store books or supplies in fume hoods.
  
  
• Since January 1, 2008, fume hoods must have quantitative airflow monitors (e.g., diaphragm pressure gauges, inclined manometers, vane gauges) that continuously indicate airflow status.
  
  
• Use a light plastic strip or paper streamer taped at the hood opening to check if airflow is operational.

Glassware Handling and Disposal

• When inserting glass tubing into rubber stoppers, polish or file the edges until smooth.
  
  
• Always aim glass tubing away from the palm of the hand holding the stopper and hold the glass tubing close to the hole.
  
  
• Use lubricants such as water, diluted soap solution, glycerin, or petroleum jelly. Press the tubing gently with a twisting motion to insert.
  
  
• Properly dispose of broken glassware and other sharp objects (e.g., syringe needles) in designated sharps containers.
  
  
• To handle steel wool and glass wool safely, always require students to wear splash-proof safety goggles, cut-resistant or nitrile gloves, and lab coats. Manage dust and airborne fibers by using wet-cleaning methods (never dry sweep), store materials in airtight containers, and designate specific solid waste bins for disposal.

Burner and Heat Source Safety

• Never use squeeze bottles near open flames.
  
  
• Protect tabletops from extreme heat by placing insulation pads underneath burners or heated objects.
  
  
• Ensure hose connections between burners and gas outlets are secure and protected from pinching or disconnection.