EPA Victoria said Shell had improved its benzene monitoring approach at the refinery after a review revealed an instrument was not operating properly and was recording inaccurate emissions levels.

“This inaccuracy is simply not good enough,” EPA executive director of regional services Bruce Dawson said.

“Under the terms of its licence, Shell was required to undertake continuous NATA accredited benzene monitoring, which they failed to do in the required timeframe.

“The system employed previously by the company was lacking but its inadequacies have begun to be addressed by augmenting the monitoring program using additional equipment.”

Dawson said Shell had since ordered a new and different type of monitoring instrument.

Dawson added that while the findings of the review still needed to be addressed, he was pleased that Shell had already begun to address the problem by installing additional canister sampling equipment near the Geelong Grammar school and ordering an Opsis machine to be run in parallel with EPA’s own system.

While Shell’s data was inaccurate and not NATA accredited, EPA’s monitoring results continued to show benzene levels were not above established national health based levels in the area.

Benzene – a carcinogenic substance – was the suspected contaminant that caused Chinese officials to shut down the water supply to the nine million residents of Harbin last week.

Shell Geelong Refinery external affairs manager Joan McGovern said that while the refinery was disappointed that benzene monitoring had not met expectations, it was pleasing that EPA’s audit had found benzene was not a health issue for local residents.

“More than a month ago the refinery announced the significant steps we have taken and are taking to improve our monitoring and our emissions and these improvements will continue,” McGovern said.

“The refinery’s existing air quality monitoring regime uses Cerex equipment to measure air emissions on a continuous basis and the refinery acknowledges that Cerex has some system improvements that need to be addressed.

McGovern said it would take about 12 months to receive NATA accreditation for Cerex.

“In the meantime, the refinery has pushed for accreditation to be expedited but actual timing is in the hands of NATA and the vendor,” she said.

McGovern said an Opsis machine – the same used by the EPA for its own benzene monitoring – had been ordered and would be operational at the refinery by next January.

“In the meantime, daily canister modelling is being conducted until the Opsis is in place,” McGovern said.

“The results from this canister monitoring show that air quality at the refinery is good and that our benzene emissions are about one fifth of our licence limit.

McGovern said these benzene emissions would be halved at the start of next year to meet the Federal Government’s clean fuels legislation.

Last month, Shell was fined more than $A10,000 by the EPA for breaching the conditions of its operating licence in Victoria.

The first incident was sparked in May by the sighting of an oily sheen on the waters of Corio Bay at the end of the company's Geelong refinery jetty. EPA analysis of samples taken on the day showed a match with oil coming from a jetty pipe flange.

A second incident occurred in June, with a large visible plume emanating from the refinery's Sulphur Recovery Unit stack during routine maintenance work. Shell reported an air quality problem to the EPA.