Workers from nearby businesses have told the Herald of multiple reports they have made to Auckland Council about the strong stench of gas and fumes that often comes from the site.
READ MORE: Smells reported before deadly explosion
The Fire Service and Vector both confirmed they have attended multiple callouts to the site for the same reasons.
Auckland Council has this afternoon issued a statement saying an abatement notice was issued to Salters Cartage in August.
"On 6 August 2015, Auckland Council staff visited Salters Cartage for a routine compliance inspection and subsequently an abatement notice was issued for concerns with certain ducting and internal processes," the statement said.
"Salters Cartage was asked to provide an action plan to remedy issues by the end of September."
However, there was no evidence to suggest the issues - and 60 complaints received about the smell of gas and fumes in the area in the last year - were related to yesterday's blast.
Council's General Manager Resource Consents Ian Smallburn said in response to claims about nearby workers complaining of gas fumes 60 complaints regarding gas odours in "the general Wiri and Manukau areas" have been received since August 2014.
"Staff investigate each complaint thoroughly, and at this stage we have no conclusive evidence to associate these with any particular source.
"Typically the odours were experienced over a short duration and have been reported in isolated pockets over a wide area, which makes investigating a source of origin very difficult."
The statement said staff visited the site today to "check whether there are any contaminants discharging into the estuary that need to be contained as a result of the explosion".
Mr Smallburn no further comment would be issued until the WorkSafeNZ investigation was completed.
The oil recovery scheme set up between council and Salters Cartage was handed over to another organisation in 2012.
On Salters Cartage's website, it still says the scheme is run with council.
Until this afternoon's statement, Auckland Council had not answered any questions about its relationship with Salters Cartage, the odour complaints or other safety concerns at the site.