Columbia subject headings:
Health facilities--Employees--Health and hygiene--United States.
Occupational diseases--United States--Prevention.
Respirators (Medical equipment)--Standards--United States.
Tuberculosis--United States--Prevention.
Harvard subject headings:
Princeton subject headings:
Breathing apparatus--Standards--United States.
Health facilities--Employees--Health and hygiene--United States.
Occupational diseases--United States--Prevention.
Tuberculosis--United States--Prevention.