Mr Kohlis said: "It was the only outcome for us, but we are annoyed we ever had to go through this process. We should never have been in the position where we had to jump up and down. We got to the point where it was being tested and putting people's health at risks."
Pan Pac's investment was announced in mid-2014, but was soon in trouble with fears over toxic gases emitted in testing using the new kiln and a secondary burner.
Early in 2016 four workers required medical treatment, 85 staff went on strike, staff and contractors were provided with a written reference for doctors if they had symptoms which could be linked to breathing emissions.
WorkSafe NZ also issued a prohibition notice stopping the plant from being put into use for any purpose other than safe testing.
In the letter the company said that while it still wanted to proceed with TMT production it had decided there were "too many difficulties with the current plant". It would work on a proposal for a completely separate new kiln incorporating different technology, taking care also with the location of the plant.
"In other words," said Mr Kohlis, "they're going to go through the process they should have done the first time."
Mr McNab said lives and jobs had been put at risk, and it was when he saw children playing nearby during a walk one Sunday morning he knew "something had to be done."
"The union has proven its community value," he said.