Reactions left unattended


Unattended experiments can cause serious damage to EPFL personnel, facilities and equipment. In the absence of the person who initiated the reaction, other laboratory workers may be unaware of the associated hazards. In this case, emergency responders must be informed of the experiment and the associated risks.

It is mandatory to complete and display this form from the moment you physically leave the campus.


The form is divided into 3 sections: Information, Hazards and Emergencies.

  • In the Information section: indicate the location, the duration of the experiment and information on the person in charge (name, telephone number). The person in charge must be reachable at all times at the number indicated.
  • In the Hazards section: select ALL the hazard pictograms that apply to your experiment. In addition, give a brief description of the hazards and the experience in general.
  • In the Emergencies section: use the drop-down menus and select the most suitable extinguishing agent. Also indicate the procedure to be followed in the event of a problem (use the drop-down menu or describe your procedure in your own words).


You can download the Reaction left unattended form here. You can fill in this form in English or French, using Adobe Acrobat or by hand (please write legibly).

Once printed out, this form should be posted on the door of the experiment room or on the window of the chemical fume hood.

The instructions below should be used as a guide when setting up these experiments.


Setting up an unsupervised reaction

  • Any unattended reaction involving chemicals or pressure vessels must be set up in a chemical fume hood or other approved ventilated enclosure (i.e. glovebox).
  • Unattended reactions involving flammable chemicals should be set up in chemical fume hoods equipped with an automatic extinguishing system (e.g. FirePro© system).
  • The maximum volume of flammable solvents allowed is 50 mL.


It is forbidden to leave an experiment unattended if :

  • Toxic, flammable or pyrophoric gases are used or generated during the reaction.
  • Pyrophoric or water-reactive chemicals are used or generated during the reaction.
  • The reaction is highly exothermic (Grignard reaction, nitration, hydrogenation, etc.).
  • Alkali metals or metal hydrides are used.


The following points are mandatory :

  • The sash of the chemical fume hood must be set to its lowest possible position.
  • The reaction setup should be moved as far as possible into the fume hood; keep a minimum distance of 15 cm between the edge of the fume hood and the setup.
  • Only one unattended reaction per fume hood or glovebox.
  • No storage other than that required for the reaction (no chemicals including pissettes, no flammable materials, no waste, etc.).
  • No water-cooled reactions (unless a leak detector with solenoid valve is also installed).
  • No electrical mantle heater.
  • The area immediately surrounding the unattended reaction must be kept clear of clutter. This is particularly important in the event of an emergency in the laboratory.