But the EPA will not say whether the dust posed any risk to human health.

The pollution incident happened between March 19-26 this year as “clinker” – powdered cement ingredients – was being unloaded from the bulk carrier Port Alberni at AAT’s berth 103 on the eastern side of the harbour.

The EPA, which found about the week-long incident when a member of the public complained, issued the penalty notice last week for AAP contravening its pollution licence.

None of the parties involved reported the incident to the EPA, as is required under the self-monitoring system in place in NSW.

This resulted in a caution for AAT and its contractor Qube, which was performing the work.

EPA Illawarra regional operations manager Illawarra Peter Bloem said the fine was issued because AAT’s licence requires bulk handling activities to be handled in a competent manner.

“The EPA alleges that while clinker (an ingredient of cement) was being redistributed between trucks after being unloaded from the ship to the trucks, large plumes of cement-like dust were generated over multiple days,” Mr Bloem said.

“The EPA also received complaints regarding alleged dust fallout on vehicles parked nearby.”

An EPA spokeswoman said the clinker in this case was in the form of a fine dust, made of limestone and clay.

But she would not answer the Mercury’s questions about whether there was a risk to human health, and instead tried to pass the question off to NSW Health.

The EPA conducts "risk-based” licencing of polluting premises in NSW, based on based on “the level of risk they pose”, according to the agency’s website.

But it relies on pollution licence holders to monitor and report on their own incidents, as well as reports from members of the public.

Mr Bloem said licence holders and contractors had a responsibility to prevent and control dust emissions while handling materials.