Do you mean no cases of failure from too little regulation that couldn't have been solved more cleverly by nonregulatory means, no cases of failure where the "solving" regulation didn't have problems of its own, or just that you literally can't think of any any cases ever of failures from too little regulation?
If you really mean the last, then avoiding modern-day issues so we don't get into a fight, the Triangle Shirtwaist Factory, thalidomide babies, and the Exxon Valdez oil spill seem like go-to historical examples.
I mean that I haven't heard anybody in the debate say, "Person X went to an abortion clinic in Virginia, and something bad happened that would have been prevented by these rules." So the impulse to regulate isn't due just to the easy availability of instances of under-regulation over instances of over-regulation.
A response essay written by Eliezer Yudkowsky posted at Cato Unbound for the issue Brain, Belief, and Politics:
Is That Your True Rejection? by Eliezer Yudkowsky
The lead essay has been written by Michael Shermer:
Liberty and Science by Michael Shermer