The classification is based primarily on the acute oral and dermal toxicity to the rat since
these determinations are standard procedures in toxicology. Where the dermal LD50
value
of a compound is such that it would place it in a more restrictive class than the oral LD50
value would indicate, the compound will always be classified in the more restrictive class.
Provision is made for the classification of a particular compound to be adjusted if, for any
reason, the acute hazard to man differs from that indicated by LD50 assessments alone.