Contact lenses pose several dangers. First, contact lenses can absorb and react with fumes. Second, if you were to get a liquid or solid chemical into your eye, the chemical would get under the contact lens. A contact lens would hamper efforts to wash the chemical out of your eye, thus making the damage much more severe. Tie back long hair.
Long hair can accidentally fall into flames or chemicals.
Loose, long hair can also block your vision, which can lead to accidents. Do not wear clothing which is loose enough to knock over containers on the work bench or drag or dip into flames or chemicals. No cutouts or cutoffs, tank tops, tube tops, muscle shirts, etc. The skin of your torso must not be exposed at any time in the lab. No shorts are allowed.