Drug screening will hit critical transit points around West Australia with the third phase of an anti-drug operation now targeting oil and gas workers.

Operation Redwater has swept mine sites and related areas across WA in recent months.

The second phase of the scheme saw searches at airports servicing BHP and Rio Tinto mines.

Now in its third phase, Operation Redwater officers will look at other regional airports servicing the oil and gas industry.

Heavy haulage drivers are also being targeted for drug screening in a spin-off called Operation Phaeton.

Phaeton saw 533 random breath tests administered, 200 of which were given to heavy haulage drivers.

Of those drivers, two tested positive for methamphetamine, one for marijuana, and another turned up negative results following the drug swabs.

Police officials say the operation has targeted major miners FMG, BHP and Rio Tinto so far, but the range is now being expanded to include traffic at regional airports.

The police say Operation Redwater was prompted by a number of factors, such as the arrest of a Fortescue Metals Group worker for possession and distribution of methamphetamine in the Hamilton Worker’s Camp.

“The numbers of people who tested positive for meth in the Pilbara was the highest in the state; 40 per cent of the people we drug tested were positive for meth,” Operation Redwater co-ordinator Commander Murray Smalpage told reporters this week.

“The problem was a bit broader than we anticipated, there’s synthetic cannabinoids being advertised, and fake urine available, we’ve had anecdotal evidence and intelligence about people being apprehended with urine bags concealed under their arm in case they’re called for a drug test.

“After an approach to WA police by industry, we decided we would launch Operation Redwater as a high-visibility, no-tolerance approach to highly dangerous activity on a mine site.

“When you think of the equipment they’re using, it’s just mindboggling that people would be so stupid, but it would appear they are.”