Despite being accused and convicted of previous poisonings, how did michael swango continue to work in the healthcare industry? who eventually put an end to swango's crimes?

Michael Swango continue to work in the healthcare industry because there was lack of checking system.

Explanation:

Even after killing many patients, Michael Swango still kept on working in the health care industry because of the lack of proper checking system in the hospital and more over the administrators of the hospitals were not ready to accept the fact that one of the people working in the hospital could kill his patients.

And therefore Swango was allowed to work even after he was imprisoned. The attempt to put an end to the crimes committed by Swango was done by the judge Jacob Mishler who gave the punishment to Swango about three consecutive life terms.

the difference is that white collar worker performs skills like worker as a scientist or well blue collars do physical work and they do services like being a cook.