The inquiry is probing the incident in March last year in which four people were killed and four were injured when a two-storey building under construction on the premises of Imperial Logistics collapsed on to an articulated truck.
The collapse took place as workers of Echo Prestress were busy with the final installation of the concrete roof slab, and killed Bhekuyise Moses Sibiya, France Mokhuthu Sekalu, Constandino Mapukula and Siyabonga Bhane.
On Wednesday, it emerged that Salerno had only realised at a site meeting on March13 that panels cast with mesh that had not been inspected by an engineer had already been erected.
Sandile Kubheka of the Department of Labour, who is presiding over the inquiry, asked Salerno how it was possible that his engineer had not been on site until March13, when the project began on February 23.
Salerno replied that there was not much happening at the site.
Advocate Raynard Looch, representing the insurer of one of the main contractors, JDF Construction, told Salerno he had not done his work properly.
Looch probed Salerno on the Joint Building Contracts Committee (JBCC) contract between him and contractors in relation to responsibilities.
He said Salerno had used an outdated JBCC template, while a recent version had material differences to the old one.