Original sentence: This trade in "grey market" drugs, which were not explicitly illegal but potentially prosecutable as drug analogs, became known as the "research chemical" trade; a euphemism intended to mask the fact that the chemicals were being sold for human consumption rather than industrial or research purposes
Edited sentence: This trade in "grey market" drugs, which were not explicitly illegal but potentially prosecutable as drug analogs, became known as the "research chemical" trade; a euphemism intended to mask the fact that the chemicals were being sold for human consumption rather than legitimate (or at least legal) industrial or research purposes