§ 427. Officers and nurses. Every employer of persons for work in compressed air shall:

1. Keep at the place of work at all necessary times one or more duly qualified medical officers to care for cases of illness and to strictly administer and enforce sections four hundred and twenty-six, four hundred and twenty-eight and four hundred and twenty-nine.

2. Keep at a medical lock required by subdivision nine of section four hundred and twenty-six a certified nurse selected by the medical officer or officers required by subdivision one of this section and qualified to give temporary relief in cases of illness.