The opposition to California's marijuana legalization measure is veering off into paranoid and delusional terrain in the final days of the campaign, echoing some of the more bizarre anti-pot themes more common in the early part of the 20th century when the film "Reefer Madness" worked to persuade Americans of the dangers of the drug.

The no campaign's website greets visitors with a photograph of a wrecked car and an overturned school bus, presumably filled by children killed by a stoned driver.

"On average, a drunk driver kills someone every 45 minutes," warns the campaign's website. "Recreational marijuana use in fatal crashes will increase if Prop. 19 passes. It will be legal for a driver to get high right before taking the wheel. It will also be legal for passengers to smoke pot as they drive on the freeway or in your neighborhood."

A new Chamber of Commerce radio ad warns that in a dystopian, post-legalization world a Californian could be maimed in a car accident caused by a stoned driver and then treated in the hospital by nurses high off their gourds -- all of it perfectly legal if the proposition passes, according to opponents. (The Service Employees International Union, the state's largest union of nurses, is one of the measure's biggest backers.)

Or, warns the ad, California businesses could lose millions in federal money for breaking drug laws and employees could come to work blazed with impunity.

The strategy reflects desperation on the part of opponents, according to an internal Chamber memo obtained by HuffPost. "I have experienced a great deal of difficulty in getting members of the business community to understand that the marijuana initiative on the November ballot (Proposition 19) is more about making it illegal for employers to have a marijuana free workplace, than it is about removing criminal penalties for possession," California Chamber CEO Allan Zaremberg wrote in an memo to Chamber members.

"The Chamber has just completed an extensive survey to determine the likelihood of prop 19 being passed by the voters and what arguments are most persuasive. First of all, without an opposition media campaign there is a very strong likelihood that it will pass. Most voters have made up their mind on whether marijuana possession should be illegal and there seems to be a majority of likely voters who no longer think i[t] should carry criminal penalties. On the other hand, though, when voters are told that employers would not be able to control marijuana use at work, proposition 19 is opposed by a majority of voters," he added, going on to say that the Chamber spent its own money on the survey because the campaign is strapped for cash.

The proposition, which had been leading in the polls, is now trailing. Zaremberg didn't immediately return a call requesting comment.

Of course, driving while impaired is and will remain illegal. Coming to work high would violate workplace policies except perhaps in Silicon Valley or the NBA.

"Imagine coming out of surgery, and the nurse caring for you was high, or having to work harder on your job to make up for a coworker who shows up high on pot," says the Chamber ad. "It could happen in California if Proposition 19 passes."

The ad goes on. "Employees would be allowed to come to work high, and employers would be unable to punish an employee for being high until after a workplace accident," it cautions.

"It's just stupid to suggest people could legally show up to work high," said Michael Whitney, a spokesman for the Just Say Now campaign, which is backing the measure. "It's no more of an issue than someone showing up at work drunk, and would be handled the same way."

The language of the initiative is written to prevent employers from firing workers for smoking pot in their free time. If the proposition passes, according to the California Legislative Analyst's Office, "employers would retain existing rights to address consumption of marijuana that impairs an employee's job performance."

The ad is just as misleading when it comes to the charge that it would be legal to drive while high. The LAO concluded that "the measure would not change existing laws that prohibit driving under the influence of drugs or that prohibit possessing marijuana on the grounds of elementary, middle, and high schools."

The latest survey has Proposition 19 behind in the polls.

The Chamber's opposition to the measure is counterproductive to its overall job creation mission. "I thought the Chamber was supposed to be all about creating jobs and helping small businesses. If so, they should be supporting Prop 19, which will create thousands of jobs and stimulate California's ailing economy," said Tom Angell, a spokesman for the Yes on 19 campaign.

The Chamber ad:

Ryan Grim is the author of This Is Your Country On Drugs: The Secret History of Getting High in America