Anglicare has applied to demolish the old Cookson Pibrilco factory buildings between Thirroul and Bulli to advance its plans for townhouses on the property.
This will involve the removal of hazardous materials, Anglicare's development application (DA) says.
These have been identified as asbestos, synthetics, and polychlorinated Biphenyls (PCBs), which are proven animal carcinogens and probable human carcinogens.
They have been found only in light fittings, while the asbestos found was all intact, the DA says.
The site includes a former quarry, heritage listed turpentine forest, and about 3ha of industrial buildings.
The DA says the risk of damage to flora and fauna was "minimal" because there was no need for native vegetation removal.
"Flora and fauna habitat values are highly limited for the demolition works zone and include scattered trees and shrubs for occasional foraging by urban adapted native species, such as birds and bats," it said.
"The existing structures within the demolition works zone comprise abandoned buildings that are in a state of disrepair and are highly exposed to elements due to broken windows and other damage to the buildings."