Mining companies in Western Australia are standing down workers who legally use prescription cannabis, as they struggle to determine what level of use makes an employee unfit for work.
Tom (name changed for privacy reasons) said he was stood down from working on a Fortescue Metals Group site for more than five weeks, and later resigned, over the confusion and stress caused by his legal use of medicinal cannabis.
The Chamber of Minerals and Energy told a recent WA parliamentary inquiry there was no clear consensus on how much THC in a person's system constituted impairment, but most took a zero-tolerance approach.
The ABC has seen FMG policy documents stating it will consider allowing the use of medicinal cannabis in order to be "progressive and equitable" but only if THC levels are below 50ug/L (micrograms per litre), which some users say is so low it is ineffective.
FMG's position on the use of medicinal cannabis is a response to what it says is the "growing prevalence" of the drug's use by workers throughout the mining industry.
Left in limbo
Tom received a prescription for medicinal cannabis about a year ago after a devastating family tragedy.
"I was on sleeping tablets for a year … and they didn't really agree with me," he said.
"I could actually go to sleep [after taking medicinal cannabis].
"Because you're pretty time poor up there … you need to have a shower, have dinner, and go to sleep as quick as you can."
As a sub-contractor tradesman working on an FMG site, he failed a random drug test and was sent home for five weeks despite presenting a legal prescription.
"They flew me to Perth halfway through my swing, and then I had to do a drug test in Perth, which I actually passed," he said.
"There was a bit of a debacle because they didn't know what level of impairment was good or bad to be working.
"And then, pretty much I was left in limbo for about a month after that.
"They said that I need to be under 50ug/L if I'm on site, even with my prescription, which is quite a low cut-off compared to other pharmaceutical drugs."
'Growing prevalence'
The ABC has seen FMG documents updating its medicinal cannabis policy to provide what it describes as "a progressive and equitable position on the growing prevalence of medicinal cannabis in our industry".
The documents state that the use of medicinal cannabis with a prescription is now permitted at Fortescue if approved by its chief medical officer.
But they also reveal issues with determining impairment:
"Impairment [times] also not clearly defined and vary significantly between users.
"Therefore, for safety-impacting workers, detectable levels of THC above the Australian Standard AS/NZS 4308:2008 for urine drug testing is not permitted on Fortescue sites or greater operation."
50 micrograms 'very trace' amount
Dr Matty Moore, a Dunsborough GP authorised to prescribe cannabis to patients including Tom and other fly-in, fly-out mine workers, said it was difficult to determine how much would push a patient over a 50ug/L limit.
"But 50 micrograms is a very small amount," he said.
"Any real dosage of THC, even a week out, can [register] positive for 50 micrograms.
"It's very trace.
"If you have any kind of cannabis with THC in it you're going to pop positive for 50 micrograms."
He said he did not believe someone with 50 micrograms of THC in their blood would be impaired.
However, the Royal Australian College of General Practitioners told the inquiry it did not support medicinal cannabis, and wanted more research done.
But it said there was a need for debate about 'impairment' versus 'detection' when it came to medicinal cannabis and driving.
Report says change needed
Last week, the WA parliament's Select Committee on Cannabis and Hemp recommended reforms to the way medicinal cannabis was regulated.
But the mining industry urged caution.
In its submission, the Chamber of Minerals and Energy said the lack of consensus on impairment, led to the current strict approach.
"Due to this, companies generally take a zero tolerance to cannabis use, aligning with the approach taken by WA police in relation to drug driving," it said.
Couldn't wait for their decision
Tom said after being off-site for more than five weeks, FMG said it would allow him back on-site — but he had already found another job.
He would have had to submit to drug tests every four to six weeks, and test below 50ug/L each time.
Tom said it was a stressful situation for resources workers legally using cannabis, even off-site.
"A lot of other people are scared and that's just the financial stress of losing their jobs," he said.
A spokeswoman for Fortescue did not comment directly on Tom's case, or its policy on medicinal cannabis.
She said the company's alcohol and drug policy ensured team members were fit to perform their role safely, and all workers and to declare any medication which might impair their fitness for work.
