Toyota Repair: Toyota tech messed up oil change, engine warranty, oil tanks

Question
Appreciate the time you're taking to answer questions.  

2002 Camry, 35,000 miles at time of incident (3 months ago) Original owner, always dealer serviced on time. Oil changes each 3-4,000 miles.

My car was the second vehicle to enter Toyota shop one morning for routine oil change only.
After oil change I watched my vehicle blow HEAVY white smoke from exhaust as tech started it up and drove it out of bay.  I Followed on foot out of service bay and watched "tech" rev engine! More white smoke.  Tech drove Camry back inside, Service manager closed down oil tanks claiming contaminated oil.  They filled with bottled oil and there was no problem after that.  Main manager wasnt in until a few days.  I met with him demanding an answer and he said his tanks were tested and it Wasn't contamination.  He refused to say what it was or thought it was.  He offered to change the oil again and I did just in case it was contaminated.  I made an incident report with Toyota regional office but since the car is running ok, I couldn't get my engine warranty extended..they only promised to resolve any future problems related to that incident. (which they never agreed upon what it was that caused it!)  I do have a receipt from that day saying contaminated oil however.

My question is:  What did they do to cause white smoke out the exhaust after only a routine oil change?  An overfill?  How will I know if damage occurred even though my car runs good now?

My piece of mind is shot because of that incident.

Thanks for any insight.

David

P.S.  I have an '88 Toyota truck, daily driver 235,000 miles and I do all the work on it.  Never had a foul up like that.

Answer
The only thing that causes white smoke,ie: steam, is water, so my best guess is that the oil tanks were contaminated with water for some reason, if the problem was corrected right away as you said and the oil was changed and the engine is running normal with no smoke, I recommend you let them change the oil again and stop being concerned about it, I really don't think any damgage was caused by running the engine with the contaminated oil for that short of a time, we had the same thing happen about a year ago and after all the people that had oil changes done were called and returned to have the oil changed again, there was not one incident of any major problem even after the customers drove the cars for several miles.
And by the way, you have a powertrain warranty that is good for 5yrs/60,000 miles, so if there should be a problem it is covered under the warranty until then.