Viva Energy, which operates the former Shell Geelong refinery, is under criminal investigation over a 9800 litre chemical spill into Corio Bay.

Details of the August 2014 spills and subsequent EPA investigation only came to light yesterday after inquiries by the Geelong Advertiser.

The spills, of 3500 litres and 6300 litres of an ammonia derivative chemical used in refining, occurred on August 22 and 23 last year, and the EPA said it was not told of the spills “until several days later’’.

The cause of the spill is also under investigation by the EPA, as is the fact that the Environment Protection Authority was not informed immediately. Any possible fine would only be determined after the investigation.

EPA South West manager Jason Young said the spill was “ a major investigation.

“It is a criminal investigation,’’ he said.

Asked why the public was not informed at the time of the spills, Mr Young said that by the time the authority heard about the spill it would have been diluted to the extent that it would not cause any human discomfort.

Mr Young said there were no reports of fish being killed.

The chemical involved was diisopropylamine (DIPA), which can cause irritation to the eyes, skin and respiratory system and harm aquatic organisms.

Geelong Environment Council president Joan Lindros labelled the spill as disgusting.

“I’m horrified that a spill of that nature has happened — firstly that nobody knew — and we wonder what do they have to pay for all this,’’ Ms Lindros said.

“There should be a significant fine.’’

The EPA issued Viva Energy with a pollution abatement notice last week relating to the spills.

The notice requires Viva Energy to install controls so that leaks or spills of DIPA are prevented in the future. The EPA said it was also looking into the current controls Viva had in place to prevent the discharge of pollutants into the atmosphere from its site to neighbouring properties that were above its licence limits.

A spokeswoman for Viva Energy said that the company accepted the pollution abatement notice that was issued by the EPA.

“Amine is a water-based solution that is used in the refinery process and is stored in above-ground and underground tanks,’’ she said. “Regrettably amine was lost from these tanks during routine transfer operations and entered the stormwater collection system.

“From here it was mixed with cooling water, which substantially diluted the product before it was released to the bay.’’

The spokeswoman said measures were in place to reduce the risk of overflows and that the company was “disappointed that this incident occurred’’.

Extracted in full from Geelong Advertiser.