A person who tests positive for TB has been exposed, but it doesn't mean they have the disease. If they don't, there's no quarantine. If sputum tests are positive for TB, they have pulmonary TB and are usually put in some modified form of quarantine (staying home, not working) until the tests are negative. Maybe a few weeks.
TB is difficult to catch, compared to many diseases. Ultraviolet light, as in out-door sunlight kills the bacteria.

If you ever once test positive for TB, you're likely to always test positive. If you've ever been immunized (questionable effectiveness), you will likely always test positive. If you've EVER tested positive for TB, you should never, ever, EVER receive the test for screening purposes again.

Controlling Tuberculosis in the United States
Recommendations from the American Thoracic Society, CDC, and the Infectious Diseases Society of America

And yeah, HIV is a public health issue because it's communicable. However, are we comparing smoking in the work place to having unprotected anal sex in the workplace, or what?