You are quite correct, Jon - neither Toluene nor MEK are regarded as being carcinogenic (except in California, where apparently EVERYTHING is) and the effects on the nervous system are reversible to a certain extent, unless exposure is very high & prolonged.  I think the quantities that we use building a typical model are of no concern at all if we are exercising common sense with respect to ventilation.

Regards
Paul W.

Whangarei, NZ
NYCSHS #7172