Just a small amount of tetra-ethyl-lead gasoline additive will ruin the 'solid electrolyte' of either a narrow or wide band oxygen sensor by coating the surface.
The gasoline additive MMT will also do this,
http://en.wikipedia.org/wiki/Methylcyclopentadienyl_manganese_tricarbonylbut slower than lead.
MMT can be legally used in 'no-lead' gasoline in Canada, but is used much less these days with ethanol blends.
MMT is in almost all the 'octane booster' that can be bought at auto parts stores.
The motor oil additive ZDDP
http://en.wikipedia.org/wiki/Zinc_dithiophosphatewill also slowly ruin an oxygen sensor if a particular cylinder is burning a good bit of lube oil for some reason. The EPA also believes ZDDP ruins the catalytic converter over time, but that is a bit controversial.
Some O2 sensors by design allow a tiny bit of air to diffuse into the sensor through the electrical wiring leads, and can go bad if excessive water comes in through this route:
http://en.wikipedia.org/wiki/Oxygen_sensor#Sensor_failures