Some lifeguard agencies worry that maintaining a drug-free workforce will become more difficult as marijuana goes mainstream.

The recent election cycle saw four more states vote to legalize recreational pot. California, Nevada, Maine and Massachusetts now join Colorado, Alaska, Washington State, Oregon, plus Washington, D.C., where it’s perfectly okay for those 21 and over to smoke weed. It won’t be a criminal offense much longer in Canada, either.

It’s a troubling trend for some lifeguard employers. After all, this industry prizes alertness above all else. These employers fear weed’s decriminalization will make it harder to hire sober-minded help from an already shallow labor pool.

“I think it’s going to be more difficult to find [applicants] that are going to make the cut,” said Ed Castillo, chief of lifeguard/EMS operations with Golden State Lifeguards.

The suburban Los Angeles-based firm provides safety services for Hollywood productions and celebrity events. The passage of California’s Proposition 64 prompted him to double down on drug screening efforts -- something he’s only had to do intermittently in the past. Effective immediately, prospective employees who are old enough to imbibe will be subject to a mandatory pre-employment drug test. It will include a hair-follicle analysis to identify if residual THC, the mind-altering ingredient in cannabis, is found in the bloodstream. The firm will institute random drug tests for all current employees, as well.

“Clients who are paying that kind of money for this service, they want people alert and on their A-game,” Castillo said.

The law is on his side. Employers still maintain the right to enforce drug-free workplaces as they see fit.

It might be more difficult for Canadian lifeguard agencies to weed out applicants who partake. The country is on the cusp of sanctioning the drug nationwide. When that happens, it will be up to each province or territory to regulate it.

Canada already has lenient laws when it comes to alcohol. The legal drinking age is 18 or 19, depending on the province. Likewise, pot could be permissible for older teens.

Already, a good number of lifeguards seem to be using.

Cheryl Sibany, aquatic safety chair for the Lifesaving Society, Canada’s official lifeguard certifying body, polled nearly 250 active lifeguards over the summer to determine how young people use marijuana, and gauge their understanding of how it impacts job performance.

The findings, published in Swim Life Magazine, show that more than half of respondents said using pot before or during a shift either had no effect or a positive effect on their ability to provide safety supervision.

“What we’re dealing with are 16 to 24-year-olds," said Sibany. "That seems to be the age group that’s responding in a positive or banal way.”

And, just like in the U.S., teens and young adults make up the brunt of the lifeguarding workforce in Canada.

Further complicating matters: Most Canadian employers in recreational industries do not administer pre-employment drug tests. That’s because the majority of applicants are minors, Sibany said. Plus, given the number of positions agencies have to fill every season, “that would make hiring really ridiculously expensive,” she said.

In light of the survey’s findings, Sibany believes the industry needs to do more to reinforce the message that pot has a negative impact on reaction time, motor skills, tracking, attention span and other critical qualities of a professional lifesaver. Young pool supervisors, too, should become empowered to identify signs of intoxication among staffers and pull them off duty, she said.

Without drug screening policies, “we have to tackle it in another way,” Sibany said, “which is through education, strong policies and empowerment.”

Sibany is inviting the international aquatics industry to participate in two more surveys: One will gather data on lifeguards' attitudes toward marijuana -- expanding upon the original study she did on Canadian lifeguards. (Click here for survey.) And another will get a picture of organizational policies concerning a guard's fitness to work. (Click here for survey.)

Correction: An earlier version of this article incorrectly stated that the Lifesaving Society researched lifeguards' attitudes toward marijuana. Cheryl Sibany, aquatic safety audit chair for the organization, conducted the survey as part of an independent study for her publication, Swim Life Magazine. AI regrets the error.