Driving from the north into Wollongong's CBD, you could be forgiven for thinking a very large circus had set up at the edge of town.
But, as you get closer, it's clear the massive white big tops lining the western end of Smith Street have nothing to do with clowns or performers.
They are part of the latest stage of remediation works for the old Wollongong gasworks, which operated between 1883 and 1977.
When it closed, the above ground infrastructure was demolished and other parts of the site were filled in, but - according to gas company Jemena's 2019 environmental assessment of the site, a range of concerning contaminants had remained in the soil and groundwater ever since.
These included a number of substances which could be harmful to humans, like heavy metals, petroleum hydrocarbons, asbestos, lead, cyanide, nitrates, sulfate, sulphides and ammonia.
Concentrations of these in the most impacted areas of the site were found to be "above the relevant assessment criteria" and could "pose a potential risk to human health and the environment".
Remediation of the northern part of the gasworks, now owned by neighbouring landowner Collegians, including the removal of the in-ground gasworks structures and excavation of gasworks impacted materials was undertaken in 2005.
These excavated materials were stockpiled along the rail line, and then removed in late 2018.
Demolition and remediation of the site at 120-122 Smith Street has been underway for almost two years, with the structures most recently home to the Housing Trust knocked down in 2019.
Remediation work began in February.
Jemena, which is spending more than $20 million to clean up the contaminated land, said this week's construction of the tents - also known as environmental control enclosures - was a significant milestone for their project.
"This is an important next step in the remediation of the former Wollongong gasworks, and means we can now commence formal excavation of the site," the company's project director Oliver King said.
"To limit the impact of the remediation works on the community we have installed an Environmental Control Enclosure."
"The ECE is designed to minimise construction noise, limit the spread of dust, and manage odour."
The structures are often used in remediation projects - a number were used during the excavation of the gasworks at Barangaroo - and are designed to provide a temporary enclosure over a site while excavation works are carried out.
The tents also allow work crews to continue with remediation works regardless of weather conditions.
The big top structures are expected to be in place for about four to six months, the company said, after which it will seek sign off from the Environment Protection Authority.
It will then "consider its options regarding the future of the site", which is in a sought-after CBD location.
According to the company's environmental review, the aim will be to clean up the land so it is suitable for commercial land use at ground level with no basements, and "medium to high-density residential land use on the top floors with minimal access to soils".
The unimproved land, which covers 1.6 hectares, is valued at just under $8 million, according to the NSW Valuer General's latest data.