The magnet contains relatively large quantities of liquid  helium and  nitrogen. These liquids, referred to as cryogens, serve to keep the magnet core at a very low temperature.

Because of the very low temperatures involved, gloves, a long sleeved shirt or lab coat and safety goggles should always be worn when handling cryogens. Direct contact with these liquids can cause frostbite. The system manager should regularly check and make sure that evaporating gases are free to escape from the magnet, i.e. the release valves must not be blocked. Do not attempt to refill the magnet with helium or nitrogen unless you have been trained in the correct procedure.

Helium and nitrogen are non-toxic gases. However, because of a possible  magnet quench, whereupon the room may suddenly fill with evaporated gases, adequate ventilation must always be provided.