Today is 420, a big day for pot smokers. So we share information about the origins of the stoner holiday — and some unfortunate events that share the otherwise light anniversary.

At the risk of being a buzzkill, National Surprise Drug Test Day is (likely not coincidentally) Friday. So we also examine marijuana testing, potency and DUI reports.

WHAT IS 420?


The term 420 has been associated with marijuana since the 1970s, according to the fact-checking site

The term originated in 1971 in San Rafael with some high school students who met at 4:20 p.m. on a regular basis to go on a search for weed. Some of the students were Deadheads, fans of the Grateful Dead, a band that formed in nearby San Francisco. The term became popularized by the band’s fans and since has become an icon of marijuana culture.

The California bill regulating marijuana use for medical purposes in 2004 was Senate Bill 420.

On the dark side

April 20 also marks Adolf Hitler’s birthday and the 18th anniversary of the Columbine High School massacre in Colorado.


Annual positive rates for illegal drugs in urine drug tests by Quest Diagnostics. There were 9.5 million tests in 2015.


Percentage of drug tests that were positive for marijuana use by ZIP code for 2015.


The Society of Biological Psychiatry analyzed samples taken from Drug Enforcement Agency seizures year by year. The overall potency of tetrahydrocannibinol (the most psychoactive cannabinoid in marijuana) in the marijuana seized in 2014 was three times greater than that of the pot available in 1995.


According to the marijuana experts at High Times, the highest percentages of THC found in marijuana have been from Colorado and measured over 30 percent. The 30 percent barrier was broken at the High Times Cannabis Cup competition in 2015, with one brand having 32.13 percent THC.


Adult possession of marijuana became legal in the state of Washington on Dec. 6, 2012, and retail stores selling pot opened in July 2014.
The drivers in the majority of fatal accidents between 2013 and 2014 had a combination of alcohol and active THC in their blood. The number involved in fatal crashes who tested positive for only THC rose 48 percent in the same period.

Proportion of DUI tests positive for THC in Washington: