Recent excavation works to install a new stormwater trench within the helipad area of Concord hospital created an occupational exposure risk to workers.
JMBEC was engaged to prepare an Occupational Health and Hygiene Management Plan, and to act as the on-site occupational hygienist during the excavation works.
As the stormwater trench was to be completed within reclaimed land that formed the helipad, the works disturbed the legacy of past historical contaminating activities from the surrounding industrial properties and from the hospital itself. During previous investigations by EI Australia, it was found that the soils contained friable and non-friable asbestos, with elevated concentrations of polycyclic aromatic hydrocarbons (PAHs), lead, nickel and dioxins which are all potentially hazardous to workers.
Despite the simplicity of completing the approximately 120m trench to a depth of 1.5m and a width of 2m, there were numerous delays due to the water-based challenges of excavating next to a major river. This resulted in a modification of the methodology used by the civil contractor to include the installation of sheet piles along the southern section of the trench, and excavations extending approximately a metre below the original scope.
All works were completed under asbestos removal conditions, with workers wearing personal protective equipment to ensure there was no contact with the soils being removed. JMBEC undertook a range of occupational exposure assessments throughout the project, including heat stress, inhalable dust and PAHs. The discovery of petroleum odours during the excavation of soils required an assessment of the subsurface gases to determine if there were any additional impacts to workers from organic compounds such as benzene. To ensure the respirators worn by workers were suitable, JMBEC also undertook respirator fit testing of both the half-face and full-face respirators for a number of workers throughout the works program.