"We tend to see people abusing the product, not following the instructions, or mixing with other drugs. So we think it is a good opportunity to remind the public to show restraint and follow our guidelines."
The majority of those in the industry were concerned by some "irresponsible members of the industry" who were causing all the issues, by changing the potency, selling to dairies, and not providing adequate advice to retailers.
Asked if the products were safe he replied, "they are low risk, they are not safe".
"No psychoactive substance is safe, but these are low-risk products.
"I know people who have been using them for years and years and years without any problems whatsoever."
Mr Hall said incidents such as the five reported cases of renal failure could be attributed to people not consuming the product "as per the instructions or the guidelines".
"That is why we want to remind the public that these products are low risk, but low risk does not mean no risk."
Asked if he smoked synthetic cannabis, he replied, "No I don't".
Star Trust represented about 80 per cent of New Zealand suppliers, manufacturers and distributors of legal high products, and its establishment earlier this year was prompted by the Psychoactive Substances Bill.
The trust was in the process of setting up a new standard for members that aimed to be above the standard proposed in the Bill, he said.
That standard would include training for retailers and involve harm minimisation strategies, with the age-restricted product to be sold at specialist stores and not from dairies.
He acknowledged there were those in the industry just out to make a "quick buck", at the expense of the wider market.
Despite negative media publicity concerning synthetic cannabis, retailers had reported no reduction in sales.
He praised the Bill from United Future leader Peter Dunne but hoped the benchmark would not be set too high for the legal high industry so no product could become legal.
"Then the Bill is a failure . . . and just another form of prohibition".
A Government analysis of the industry estimated it had a retail turnover between $25 million and $35 million, and "no-one has denied that is accurate".
"This industry pays taxes. It is not like the black market."