An investigation into how asbestos was managed in Christchurch after the 2011 earthquake has found some deficiencies but no reason to prosecute anyone.
WorkSafe New Zealand has completed its review of asbestos management in the Canterbury Home Repair Programme.
WorkSafe launched the inquiry earlier this year after allegations surfaced about possible inadequacies in the Earthquake Commission (EQC) and Fletcher EQR's systems for identifying and managing asbestos hazards during early stages of the Canterbury rebuild.
Gordon MacDonald, WorkSafe chief executive, said the investigation did find some deficiencies in the management of asbestos during early parts of the Home Repair Programme.
However, WorkSafe said the risk of harm to workers and residents was very low and prosecution was not justified. The risk to residents was likely to have been even lower, WorkSafe said.
"Given the scale of work in Canterbury it's inevitable there were instances where work was not up to best practice and our investigation did identify shortcomings with the management of asbestos," Mr MacDonald said.
"It has to be remembered that in the weeks and months after the Canterbury earthquakes there was an incredible amount of work done - both demolitions and emergency repairs. People and organisations were stretched and conditions were far from ideal," he added.
Mr MacDonald said contractors had significantly improved the way they managed asbestos. He said WorkSafe and its Canterbury Rebuild Safety Charter partners had also educated tradespeople and contractors about health risks asbestos posed.
WorkSafe said the investigation included reviews of EQC and Fletcher EQR documentation, their systems and processes. It also included interviews with management, contractors and residents.
Investigators also carried out property inspections and asbestos testing in a few houses - including surface and air testing.
WorkSafe said it also hired independent experts to review research conducted on behalf of Fletcher EQR into breathable fibre release during certain types of repair work.