Ballance Agri-Nutrients has been fined $82,500 for an unauthorised discharge of contaminants, namely sulphur dioxide, into air from their fertiliser manufacturer plant in Mount Maunganui.

Ballance Agri-Nutrients pleaded guilty the charge relating to an incident on May 22 2017 where a build-up of fumes were discharged into the air in the form of a 20-30m gas cloud.

The build-up was caused by a lack of communication during staff handovers about a change in process settings which prevented the gas from being properly extracted.

This led to the fumes bypassing the treatment system, and drifting towards Totara Street beyond the property boundary, says a statement from the Bay of Plenty Regional Council.

Those who were exposed to the gas cloud, suffered temporary effects ranging from a metallic taste to difficulty breathing, and two people needed to be hospitalised.

One of those hospitalised was exposed to the discharge while walking along Totara Street.

During the hearing, Judge Kirkpatrick reflected on the preventative measures which Ballance introduced since the offending.

'These really only serve to indicate what might have been done earlier to ensure that such discharges did not occur,” says Judge Kirkpatrick.

Judge Kirkpatrick considered that the two previous prosecutions relating to Ballance's fertiliser plant at Mount Maunganui for similar offences in 1999 and 2014 were aggravating factors in this case.

Like the previous offences, the present case involved shortcomings in Ballance's operational and emergency processes and temporary health effects to people at and near the site.

Regional Council Compliance manager Alex Miller says things like sulphur dioxide and fluoride can have significant effects on both the environment and human health, so it's critical that commercial operations that generate these contaminants are well managed.

'While this event was an accident, caused by a series of fundamental errors at the fertiliser plant, with a main road on one side and the Whareroa community behind on the other, the fact that more people were not affected was a matter of good fortune rather than good management,” says Alex.

'Unfortunately, we've undertaken prosecutions for similar offences at this site three times now, with the most recent in 2014.

'We hope that the measures which they've put in place after the offending mean that we don't arrive here ever again.”

Fertiliser is manufactured at the Ballance plant by mixing finely ground phosphate rock with sulphuric acid, water and recycled scrubber liquor in a reaction vessel.

The mixture is solidified in an acidification den and a number of by-products are generated as a result, including gaseous fluoride and sulphur contaminants.

To view a copy of the sentencing decision click here.