According to WBBM newsradio
Beginning next fall, St. Patrick’s High School, on the northwest side, will become the first in Illinois to require drug tests of ALL its students.A number of public schools require students who participate in extra-curricular activities to undergo drug testing, but are barred by Supreme Court ruling from extending such tests to all students. Principal Joseph Schmidt said he considers the all-boys school, at 5900 W. Belmont Av., the “catalyst” in Illinois for universal testing.

The origins of 420 written by its founders: CounterPunch: The Etymology of 420