The Coroner's inquest into the death of senior firefighter Derek Lovell is complete with its final day focused on knowledge gaps and regulation failures in the refrigeration industry.

Derek died from injuries sustained in the explosion of a refrigeration plant at the Icepak Coolstores in Tamahere in 2008.

The last witness to give evidence was Brian Jackson, founder of the Institute of Refrigeration Heating and Air-Conditioning Engineers.

He says a lack of knowledge is a key problem for the industry.

'Emphasis has been placed on education for new people to the industry, but there is a large amount of education needed for upskilling people already in the industry.”

The Tamahere coolstore was identified as noncompliant in an inspection in 2006 after its refrigeration plant had undergone a refit so it could use a hydro-carbon gas instead of ammonia.

The refit was not done to standard owing to the technician's lack of knowledge of systems required for safe use of the flammable hydro-carbon gas.

The work was inspected and identified as noncompliant in 2006, but owing to perceived flaws in the industry's regulations, this hazard was not properly communicated to those legally responsible.

This was Icepak Coolstores managing director Wayne Grattan, who also spoke at the inquest.

'I had no knowledge of the operating dangers, quite to the contrary as we were operating environmentally friendly refrigerants.”

The remedy suggested at the inquest by Institute of Professional Engineers of New Zealand member John Richards was for direct communication and action on the part of the inspector.

He proposed inspectors directly notify site owner/occupiers and then have the facility shutdown if noncompliant.

Other issues explored at the inquest were the New Zealand Fire Service's response process to gas leak emergencies and shortcomings in the licensing system of refrigeration inspectors.

Written submissions from the inquest now have one month to be filed with the Coroner before he makes recommendations on how to improve coolstore safety.