A drug dealer sold hundreds of thousands of doses of a cleaning product with a high concentration of the drug GBL, after purchasing it from an unwitting company that believed it was for commercial purposes.

Through eight separate orders over three and a half years, Justin Rankin, 36, paid nearly $100,000 for 2214 litres of the product, which the company imported from the United States. It is believed the operation netted him an estimated $1.7m in profit.

The industrial plastic mold cleaner, which is used during the plastic manufacturing process, contains 50-80% of gamma-Butyrolactone (GBL) – a substance typically used recreationally to induce euphoria, enhance sexual activity and in combination with methamphetamine.

GBL is so potent that the standard dose is 1ml-3ml. It sells for about $3-$5 per millilitre in New Zealand and the difference between the desired effect and an overdose could be a matter of millilitres.

READ MORE: * Wellington man charged with 'enormous' 2000-litre 'date rape' GBL drug importation, equivalent to $288m of community harm

It is understood Rankin was selling the cleaner as GBL, despite it also containing N-methyl-2-pyrrolidone (NMP) – a solvent for surface treatment of textiles, resins and metal-coated plastics.

On Monday, before the start of a 10-day trial, Rankin pleaded guilty to five charges: Supplying 1798 litres of GBL, possessing 400 litres for supply, possessing equipment capable of manufacturing methamphetamine, possessing methamphetamine for supply and driving while disqualified.

Details of two separate investigations by Wellington police were laid out in a summary of facts, revealing he first came under suspicion in July 2019.

Police suspected his involvement in the manufacturing and selling of methamphetamine and the selling of GBL, leading to the launch of Operation Paris. Rankin’s Wellington home was searched four months later.

Police uncovered a near-empty 19-litre drum containing the cleaner, as well as syringes, a tube, a bottle and a measuring jug for decanting and dispensing, thousands of dollars in cash, meth and multiple products used to manufacture meth.

Several months later in June 2020, while on bail for offences stemming from the search, Rankin was pulled over in a traffic stop, having only been disqualified from driving two days earlier.

A search of his vehicle found numerous items that went on to unravel his wide-ranging drug operation – transport consignment notes, packaging slips and a plastic label – all of which showed he had purchased large quantities of the cleaning product from an American supplier, through the New Zealand company.

Police also found syringes, scales, GBL, resealable bags, $6000 in cash, methamphetamine and equipment to make methamphetamine. Hidden under a wooden panel was another $3700 in cash.

Rankin’s cellphone data uncovered numerous messages about the selling of drugs and identified several locations around the city where he had stored the GBL. They also revealed evidence of internet searches including “how to make methamphetamine” and “what is crystal meth made from? main ingredients”.

CCTV footage also showed Rankin visiting the storage locations.

A joint investigation between police and Customs – Operation Skipjack –was soon launched. Rankin’s home was searched again, along with several other locations around Wellington.

This led police to find 400 litres of GBL – the largest seizure of the drug in New Zealand’s history. Police at the time described it as “enormous”.

An excess of 20 kilograms of eutylone was also found, along with a clandestine methamphetamine lab.

The drugs had a combined street value of more than $5m and a social harm index cost of more than $30m.

Around the same time, in November 2020, Dr Paul Quigley, from Wellington Hospital’s emergency department, warned there had been a rise in GBL overdoses. Patients were admitted “deeply unconscious, potentially not breathing and requiring life-support”, he said.

Police initially said the GBL had come from China, but the second investigation uncovered Rankin had contacted the New Zealand company, which Stuff has chosen not to name due to other legal proceedings, which then imported the product from an American business.

Rankin said he was associated with Stoneybrook Construction and needed the product to clean his trucks. He had previously been the director of the company, but it was deregistered in 2012.

A spokesman for the New Zealand company used as the importer said it was not guilty of any wrongdoing and was an innocent party in Rankin’s crimes.

“The product that was imported was a legitimate cleaner and Justin Rankin purported to be a legitimate user of this product.”

Once the company became aware of the misuse of the product in December 2020, it advised the supplier, he said.

“At which point the product was immediately banned from export to New Zealand. We have fully assisted the police in all matters relating to his conviction.”

Rankin is due to be sentenced in November. Several others allegedly involved in the drug operation are still before the courts.