The survey by Leicester City Council found they could not prove they were disposing of their scrap tyres legally. The dealers in question could now face fines of up to £5,000.
Councillor John Mugglestone said: “This was a very useful exercise to deal with a major problem. There were more than 650 incidents of tyre dumping reported to us last year, costing our taxpayers an estimated £30,000.”
Officers had previously said they believe the tyres are being dumped by professional environmental criminals and are coming from one or more commercial sources.
Dealers are required by law to keep records of the transfer of their waste tyres to rubbish disposal firms. Further surveillance and inspection visits in the city are expected.