§ 257. Illumination. 1. In every factory proper lighting shall be
provided during working hours for:

a. All places where persons work or pass, or may have to work or pass
in emergencies;

b. All elevator cars and entrances;

c. All halls and stairs leading to workrooms;

d. All moving parts of machinery not required to be guarded by section
two hundred and the rules of the board, and which are dangerous because
of their location.

2. In every factory workroom the lighting shall be such as will not
cause strain on the vision or glare in the eyes of workers.

3. In the public hallway upon each floor of every factory building a
proper light shall be kept burning near the stairs during each working
day from the opening of the building until its closing, except when
natural light suffices. Such lights shall be arranged to operate
reliably when through accident or other cause other lights of the
building are extinguished.