§ 428. Physical examinations. If an employee is a new employee, an absentee for ten or more successive days, an employee who has worked in compressed air continuously for three months or a beginner in compressed air who has worked but a single shift as required by section four hundred and thirty, the officer or officers required by subdivision one of section four hundred and twenty-seven shall examine him and declare him physically fit to work in compressed air before permitting him to enter or re-enter the working chamber.