Recreational marijuana could have a big day on Tuesday. Though marijuana is still illegal under federal law, five more states, including California, have recreational use drug on the ballot. CNN reports:

It’s on the ballot in California, Massachusetts, Maine, Arizona and Nevada. Voters will also decide whether it should be used for medical reasons in three other states…

Currently, it’s legal to use recreational marijuana only in four states and in the District of Columbia. Colorado and Washington state voted to OK it in 2012. Alaska and Oregon voters approved it in 2014. Medical marijuana is legal in half of US states and is on state ballots this year in Montana, Florida and North Dakota.

The most important vote will be the one in California:

A “yes” on Proposition 64 would make it legal for people 21 or older to use it recreationally. There would be a 15% sales tax, and its cultivation would be taxed. The money would be used in part to study drug research, to study treatment and to help with enforcement of the law.

The state’s two largest newspapers back the measure, as does the California Democratic Party, while Republicans are against it.

Former House Speaker Nancy Pelosi told the LA Times last Friday, “I will vote for it, but I have not made a public statement about it until right this very second.”

The results of legalized marijuana have been mixed. In Colorado the drug has reportedly generated billions in new economic activity and created as many as 18,000 jobs. But there has also been an increase in the number of people, especially pot tourists visiting from out-of-state, who wind up in emergency rooms. From a CNN story published in February:

A study of use in Colorado published in 2015 found increases in marijuana-related traffic deaths, hospital visits, school suspensions, lab explosions and pet poisonings. In that study, marijuana-related ER visits increased 57% from 2011 to 2013.

This new study from Northwestern Medicine and the University of Colorado School of Medicine reviewed ER visits at more than 100 hospitals from 2012 to 2014. Out-of-state visitor trips to the ER visits for marijuana-related symptoms rose from 78 per 10,000 visits in 2012, to 112 per 10,000 in 2013, to 163 per 10,000 in 2014 — an increase of 109% from 2012 to 2014.

Recent polls suggest Prop 64 is likely to pass in California. The legalization effort also seems to be leading in polls in Nevada, Maine and Massachusetts. The vote in Arizona is expected to be the tightest with polls showing voters about evenly split on the issue.