Well when I was reading one of his books I thought I had found an ACTUAL mistake!
He used to work "inflammable" in a context which clearly meant easily set alight.
So doing a little research on the web quickly reveals that these two words mean the same thing.
Apparently the two words have different (but related) origins in Latin. This is explained here.
The image below shows that this has caused some confusion in Springfield also.
So, of course, Mr Asimov was not wrong at all!
