Member for Hammond Adrian Pederick has offered his cautious support to a ban on fracking in the South East, despite having worked in the industry during the 1980s.
A 10-year moratorium on hydraulic fracking – intentionally fracturing rock formations to free the gas or oil that may be trapped within them – was imposed by the state government in March, in recognition of the risk of groundwater contamination involved.
But independent MP Troy Bell, of Mount Gambier, asked that the government go one step further and enshrine it in law.
The resulting legislation passed through the lower house of South Australia's Parliament on Wednesday.
Though he voted for it, Mr Pederick noted that mining added billions of dollars to South Australia's economy, and that other forms of drilling and boring were not being banned.
"I think we need to be careful where we go to," he said in Parliament.
"There would be thousands of water bores, including many hundreds in the South East, where the well integrity would be terrible, and there would be leakage between saline aquafers and freshwater aquafers.
"I just want to make that point."
He also pointed out that geothermal energy extraction used fracturing techniques which were "a lot heavier", but was not being banned either.
"But I do acknowledge the party's position," he said.
Mr Pederick spent 12 months working for Gearhart Australia during the 1980s, and operated fracking wells at Mereenie, in the Northern Territory.
He said the methods used in his time were different to those which had caused recent concern in the South East.
Drills and explosive shells had been used to open up rocks, and fracture sand pumped in afterwards to keep the cracks open.
The hydraulic fracturing which the proposed legislation would ban involved the injection of pressurised water or another fluid into rocks to do the same job.
The ban would apply in seven South East council districts: Mount Gambier, Grant, Kingston, Naracoorte-Lucindale, Robe, Tatiara and Wattle Range.