The original draft for the law had higher amounts for all the drugs. For LSD it was 0.025 milligrams (which would be the smallest possible dose). When the law w

The original draft for the law had higher amounts for all the drugs. For LSD it was 0.025 milligrams (which would be the smallest possible dose). When the law was vetoed, congress reduced the doses and voted again on it. That's the way they came up with that 0.015 milligrams.