California joined the list of states approving recreational marijuana use, as voters passed Proposition 64 on Tuesday, 56 to 44 percent.

Effective immediately, Prop. 64 allows Californians who are 21 or older to carry, transport or buy up to an ounce of cannabis. A person is now allowed to grow as many as six plants. A 15 percent tax will also be imposed on marijuana sales.

Non-medical marijuana is to be sold by state-licensed retailers. Under the measure, California has until Jan. 1, 2018, to begin issuing sales licenses to these businesses.

The new measure raises some concerns among opponents.

Kevin Sabet, president and CEO of the opposition group Smart Approaches to Marijuana, is worried about cookies, candies and marijuana edibles that appear too "kid-friendly."

"It's a massive social experiment," he said. "We're experimenting on our young people, we're experimenting on our health, we're experimenting on our roads. Look, California already has driving issues. Now, we're going to add marijuana to it. It's appalling, given how marijuana affects driving."

However, Michael Bustamante who is spokesman for the Yes on Prop. 64 campaign believes that the measure is a "model for public policy." The campaign built a large coalition of nurses, doctors and civil rights groups and the support of major newspapers such at the Los Angeles Times and La Opinión. The campaign also raised almost $16 million with the help of former Facebook President Sean Parker and billionaire George Soros.

"What this means is that Californians understand that the War on Drugs has been an abject failure, and it was time for a new direction," Bustamante said. "The only negative I can see is that it should have been passed a long time ago. There's so many people that have a criminal record that shouldn't have."

Possession of marijuana offenses have disproportionately affected Latino and African-American communities, according to Bustamante.

Some students at USC see this measure as a positive. Under Prop. 64, Californians can begin the process of clearing their records or having sentences reduced for past marijuana offenses.

"As a minority and the environment I come out of, which is South Central LA, I think it's a positive. So many people have been put behind bars for crimes related to marijuana," said Kellin Sandoval, a senior at USC.

Last night, there were nine states on the ballot that were voting either for medical use or recreational use of marijuana.

The California Legislative Analyst's Office in Sacramento determined that Prop. 64 would bring in over $1 billion a year and would reduce criminal justice costs by tens of millions of dollars.

"It will raise a lot of revenue for the state. Fix the potholes with the money from the pot," said David Chavez, a local small-business owner. "If you can go to war and die for your country, you should be able to smoke in your country."

Follow Staff Reporter Melanie Gonzalez here. Follow her on Twitter here.

Staff Reporter Terrance Davis contributed to this report.