The land at 92 Mulgoa Road, where a 7-Eleven station stands, was declared to be significantly contaminated in the Government Gazette earlier this month.

It was also found that contamination had spread from the site.

The contamination occurred through leaking underground petrol tanks — before it was a 7-Eleven site — which were replaced in 2008.

The investigation relates to residual contamination, an Office of Environment and Heritage spokesman said.

However, the Environment Protection Authority (EPA) believed there was ‘‘no evident risk to residents at this stage’’.

‘‘It is known that the petrol has affected groundwater which is eight metres below the ground surface,’’ the spokesman said.

‘‘The EPA considers the contamination low risk but still needing a regulated clean up.

‘‘The remediation will be determined once the action plan is complete and approved by the EPA.’’

Penrith councillor Prue Guillaume became aware of the contamination when contacted by a Ten News reporter.

Cr Guillaume told the Star last week she was confused as to why there wasn’t more information from the government about what the contamination meant.

‘‘They need to explain that in ways we understand.’’

Resident Robin Robinson also said last week that she wanted to see a full report: ‘‘I want something that’s genuine that I can read.’’

Penrith MP Stuart Ayres addressed Parliament on Tuesday on the action being taken.

Mr Ayres said that since the declaration, the owners of 7-Eleven had arranged a meeting for affected residents, which will be held on Saturday at 9am.

Mr Ayres accused Cr Guillaume of ‘‘whipping up fear’’, but last week she said was making residents aware of the situation.

‘‘It is unfortunate that it has taken state-wide media to make the NSW government sit up and take notice of this issue.’’

A 7-Eleven spokeswoman said on Tuesday they had submitted a voluntary management plan to the EPA and were awaiting permission from residents to conduct tests on their properties.

‘‘We’ve been keeping residents and the body corporate of 80McNaughton Street fully informed about the process and the actions 7-Eleven is taking,’’ she said.