Construction firm Kier flouted safety rules with the improper disposal of deadly asbestos in South Harrow, a damning report found.
Workers refurbishing a property in Brookside Close ripped out floor tiles and toilet cisterns and simply dumped them in an open skip, rather than arranging a specialist licensed waste contractor to collect it.
These tossed materials were deemed "low risk" - the tiles were thermoplastic and the cisterns Bakerlite - and a "neglible risk to the public". But the practice still breached health and safety policy.
The relevation is contained in a report into the incident that remained confidential until pressure by the opposition Labour party - which originally flagged up the problem - forced Harrow Council to make it public.
The report says: "As a result of accepted poor site management and inadequate quality control measures undertaken by Kier in Area 6 (Brookside Close), operatives did not receive appropriate asbestos related information.
"This failure by the site manager of Kier was in clear contravention of the company’s and Harrow Council’s health and safety policy."
It transpires that before the asbestos-dumping took place, Kier had sacked an area manager responsible for Brookside Close and neighbouring streets "as a direct consequence of his failure to work within their health and safety policy."
Councillor Bill Stephenson, leader of the Labour group, said: "I am angry and so should Harrow residents that the council has tried to surpress this report.
"It makes damning reading and catalogues the carelessness and lack of procedures as far as asbestos is concerned by both Kier, who must take primary responsibility, and the council itself is as much at fault."