what can damage an oxygen sensor?

what can damage an oxygen sensor? I have one which appears to be bad. I checked it with my volt meter. The car is also giving off an oxygen sensor code. Is there anything further back in the system which can cause them to go bad, or would I be safe just replacing \the sensor?

These sensors do not last forever, and replacing one is part of a major tune up. Some manuals suggest replacing them very 50,000 miles or so. Often, they will last longer, 80,000 miles or more, but they will go bad.
Generally, they only are damaged if they become coated with a contaminent in the fuel (leaded gasoline) or if the engine is burning lots of engine oil which has certain anti wear additives in it.
( Engine oil specifically intended for diesel engines have such additives)
I would suggest replacing the sensor, unless the wire going to the sensor is damaged.

what can damage an oxygen sensor?

A hammer

WMD

improper RTV

sulphur in gas

testing with a DVOM with less than 1Mohm resistance/volt