A few have been busted so far but with the explosion of fracking / waste in the past 15 years - there's no way for regulators to stay on top of it.
https://www.opb.org/news/article/radioactive-fracking-waste-...
> The agency found that Chemical Waste Management dumped nearly 1,284 tons of radioactive waste it received from Goodnight Midstream over a period of three years, totaling over 2.5 million pounds.
..
> Initially, Chemical Waste Management had no records of a relationship with Goodnight Midstream. But it was later confirmed that the North Dakota company contracted a third party, Oilfield Waste Logistics, to dispose of its solid waste. Shipping manifests showed that OWL was sending Goodnight Midstream’s waste to Arlington.
https://www.cleveland.com/court-justice/2014/03/fracking_com...
> The owner of a Youngstown oil- and gas-drilling company pleaded guilty today to ordering an employee to dump tens of thousands of gallons of fracking waste into a tributary of the Mahoning River.