Westminster Magistrates' Court was told on 30 August that a member of the public had raised concerns about conditions at the building site in Mitcham, south London and alerted the HSE.
Inspectors had first visited Pitcairn Road in October 2016 and found that Selliah Sivaneswaran, owner of the property, had failed to appoint a principal contractor for the development, which involved the demolition of old flats and the construction of four one-bedroom flats and two-bedroom flats.
The HSE had halted the demolition because workers were being exposed to a range of risks, including exposure to asbestos, falls from height, and fire. Inspectors had served enforcement notices and provided advice.
They revisited the site on 4 January 2017 after the tip off from a member of the public and discovered that the work had restarted, even though the site was still unsafe.
The demolition continued to be carried out by hand with workers climbing onto the unguarded roof and throwing debris down. Workers were at risk of falling up to 4 m through holes in the floor and the partly demolished staircase. Sivaneswaran had also failed to provide welfare facilities and there was a significant fire risk with workers not being able to escape.
The court was told that two days before the sentencing hearing, the HSE had to return to the site and take further action.
Sivaneswaran had paid cash in hand to untrained workers, did not engage a site manager and provided none of the legally-required site documentation.
Selliah Sivguru Sivaneswaran, of Harlyn Drive, Pinner, pleaded guilty to breaching reg 13(1) and 4(1) of the Construction (Design and Management) Regulations 2015. He was fined £200,000 and ordered to pay £1,421 in costs.