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Labour, OH&S

IWH takes deep dive into the marijuana Pandora’s box

Grant Cameron
IWH takes deep dive into the marijuana Pandora’s box

Legalization of cannabis might be great for those who want to kick back and have a weekend toke, but it has opened up a Pandora’s box for contractors who are understandably concerned about worker impairment.

A team at the Toronto-based Institute of Work and Health (IWH) is doing a deep dive into the issue, though, that might yield valuable data for the industry. Researchers are doing annual surveys of workers over a four-year period to gain more insight into their perceptions about cannabis use, reasons for using it, and how workers are using cannabis, specifically whether they’re using it before or at work.

Findings from the work will help identify gaps in knowledge, problematic perceptions and risky use patterns.

Initial results, however, may be a concern for construction employers. A survey conducted in June 2018 about four months before legalization of cannabis came into effect showed that roughly one quarter of workers in Ontario, British Columbia and Atlantic Canada reported using cannabis within two hours of starting work.

Twenty-five-per-cent of respondents in Atlantic Canada indicated using cannabis within two hours of work, while in Ontario and B.C. it was 24 per cent. The overall average across the country was 22 per cent. Quebec recorded a rate of 22 per cent; the figure was 18 per cent in Saskatchewan and Manitoba, and in Alberta it was 14 per cent. Results of a second survey conducted post-legalization in 2019 are still being analyzed, and two more are scheduled this year and in 2021.

Nancy Carnide, associate scientist at the IWH who is co-leading the studies with Dr. Peter Smith, senior scientist and scientific co-director at the IWH, and others from the Institute and University of Buffalo, says the first survey showed some workers in the sample were already using cannabis in potentially risky ways.

Workers who used cannabis also reported using cannabis primarily for a mix of non-medical reasons such as relaxation, feeling good and special occasions, and medical reasons such as sleep, pain, stress and anxiety purposes, Carnide says, while almost 40 per cent reported that their reasons for using cannabis were specifically related to their work issues for things such as managing stress and pain relief.

“Most workers felt that consuming cannabis at work was risky, although they felt that cannabis use two hours prior to work was less risky,” she says.

“There were also knowledge gaps demonstrated by workers in this pre-legalization sample, with respect to knowledge of the timing of effects after cannabis consumption, the availability of a workplace substance-use policy in their workplace, and whether use at work would be permissible after legalization.”

Also of concern, 21 per cent of those who used cannabis believe it causes no risk or only a slight risk of causing harm to themselves or others when it is used within two hours of doing hazardous work.

Carnide says cannabis use on construction sites can result in impairments in cognitive and psychomotor function and include impaired memory, difficulty concentrating, reduced attention span, poor co-ordination, slower reaction times and reflexes, altered sense of time, and altered space perception.

“Impairments such as these can pose an important safety risk for anyone on a construction site engaging in safety-sensitive tasks, such as operating machinery or working from heights.”

How long such impairments last and the extent to which someone experiences the effects depends on a number of factors, Carnide says, including method of consumption such as inhaling versus ingesting, how much is consumed, typical frequency of use, whether consumed with other substances at the same time such as alcohol, and the potency of the product consumed, namely the THC content.

Employers need to ensure they have clear policies in place, not only on cannabis use, but on all substance use and impairment, and all such policies need to be well-communicated to workers, she says.

“But,” she adds, “simply having a policy may be insufficient. In addition to knowing what is expected and permissible in their workplaces, workers appear to also need education on cannabis fundamentals, such as the different components of the cannabis plant, the potential effects of cannabis, and how these effects may differ depending on method of consumption, among other factors.

The first survey was completed by 2,014 workers. The 2019 survey was completed by 1,099 workers from the original sample plus an additional 3,002 workers.

Questions were asked about their perceptions of the risks associated with workplace cannabis use and their knowledge of the permissibility of workplace use after legalization. Those who reported cannabis use were also asked questions to better understand their use patterns, cannabinoid content of the cannabis they used, their use before and at work, and their perceptions of the impact of their use on work.

Over the next two years, the IWH will follow up with workers in the study to evaluate if anything has changed with respect to their cannabis use patterns and perceptions.

“We are also interested in understanding what workers know about cannabis effects, what their perceptions are about workplace cannabis use, and what the norms are around use in their workplaces,” says Carnide.

“By surveying workers from pre-legalization through post-legalization, we hope to better understand how all of these factors are changing over time. We are also examining how these factors differ according to worker and workplace characteristics.

“This information can potentially be used to inform the development of educational initiatives targeting workers in order to mitigate the potential occupational risks of using cannabis.”

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