Marijuana plants

Aari Ruben at his medical marijuana dispensary and grow operation on Tucson’s south side.

PHOENIX — With the fate of legalized marijuana in doubt, supporters and foes of Proposition 205 are amassing cash for a last-minute blitz to convince voters.

A new poll of 550 Arizonans conducted this past Tuesday and Wednesday finds the ballot measure leading — but only slightly.

Of those questioned, 48 percent said they are likely to support the initiative, with 47 percent opposed and the balance undecided.

Pollster George Khalaf, who conducted the survey for Data Orbital, a Phoenix based consulting firm, said that difference is statistically insignificant, being well within the 4.1 percentage point margin of error.

With victory on the issue clearly within the grasp of either side, both are raising lots of last-minute cash to close the deal.

Reports analyzed by Capitol Media Services shows that the Campaign to Regulate Marijuana Like Alcohol has more than $5.2 million. More than $2 million of that has been donated in the last six weeks.

For the foes, the late infusion is more striking.

As of Sept. 19, Arizonans for Responsible Drug Policy had collected less than $1.9 million. But since that time, it has secured additional donations of more than $4.4 million.

Both sides can boast some major donors.

The Marijuana Policy Project and its separate foundation have put in close to $1.6 million, both to pay circulators to get the measure on the ballot and to promote it to voters.

There’s also $410,000 from Dr. Bronner’s Magic Soaps, a California firm that makes cleaning products, including those that use hemp oil. But the company says various restrictions on growing hemp — essentially a version of marijuana without the psychoactive ingredients — have forced it to look elsewhere for supplies.

This isn’t the first outing for the company, which says it donated money to previous successful legalization initiatives in Colorado and Washington.

There also was a $350,000 donation just days ago from Drug Policy Action, which advocates for the reform of drug laws.

On the other side of the fight, the Arizona Chamber of Commerce and Industry has been the main source of dollars, putting in close to $1.5 million to keep recreational use of marijuana illegal in Arizona.

And Discount Tire has contributed another $1 million on top of that. It is a private company owned by Paradise Valley resident Bruce Halle. Forbes pegged the 86-year-old Halle’s net worth Friday at $6 billion. The tire chain has more than 900 stores in 31 states with estimated annual revenues of $4.2 billion.

There also is $500,000 from Nevada casino magnate Sheldon Adelson and an identical amount from Insys Therapeutics, a Chandler firm that manufactures a spray opiate for pain relief and is seeking to market a non-psychoactive version of marijuana that could be prescribed by doctors.

Hanging in the balance of what happens Tuesday is who will be able to buy and use marijuana.

A 2010 initiative, also financed by the Marijuana Policy Project, allows those with certain medical conditions and a doctor’s recommendation to obtain a card from the state Department of Health Services as a registered user. That card entitles individuals to obtain up to 2½ ounces of marijuana every two weeks from one of about 90 state-licensed dispensaries.

Prop. 205 would extend the right to buy and use the drug to any adult, albeit with a limit of one ounce at any one time.

It also would expand the number of places where marijuana could be sold to 147 through 2020. And existing dispensary owners would have first dibs on those new permits.

Much of the campaign to date has been focused on what has happened in Colorado where voters approved legalization for recreational use four years ago.

There are various claims of whether use of marijuana by teens, who are not legally permitted to have the drug there, has increased since 2012. Much of the conclusion depends on which report is cited and what starting date is used for comparison.

Proponents of the Arizona initiative point out that Prop. 205 would raise additional money in taxes for schools. But, here too, there are conflicting claims about how much reached individual schools in Colorado.

According to Data Orbital, 455 of those questioned said they were extremely likely to vote in this election with another 88 very likely.

On Twitter: @azcapmedia