Not as bad as “inflammable”, my personal vote for the most dangerous word in the English language.
Also pretty silly for "flammable"/"inflammable" to be synonyms when "combustible"/"incombustible" are antonyms.
Does seem like folks ought to stop using the old definition of "inflammable", but if they must, seems like it ought to be spelled as "enflammable", much like "enrage" displaced "inrage".
["Rebracketing", Wikipedia](https://en.wikipedia.org/wiki/Rebracketing) has a neat discussion about the interpretation-ambiguity.