Four people are being investigated for suspected fly-tipping offences after a campaign to crack down on the practice.
Police joined Environment Agency and borough council workers to spend Thursday morning at two locations in Dudley with a history of fly-tipping.
The agency said about 20 vehicles were stopped at Himley Road and Holly Hall.
Ten drivers were also given information about how to register to get rid of waste legally during the "Tough on Tipping" operation.
'Scourge of fly-tipping'
Police motorcycle outriders checked both sites for vans, pick-ups and trucks carrying waste.
Officials were also looking out for over-laden and unlicensed vehicles, the use of red diesel and disqualified drivers.
Stuart Gamble from the Environment Agency said: "We are committed to ridding the Black Country of the scourge of fly-tipping and the Tough on Tipping operations are a valuable tool in our work to do this."
Cllr Karen Shakespeare, cabinet member for the environment said: "Since April Dudley Council has dealt with 430 fly tipping incidents across the borough and this is not acceptable.
"With the help of the Environment Agency and the police we will continue to take the problem of fly tipping very seriously.