I seem to remember that some time in the 80's or 90's, (could have been earlier) that the FEDs finally made the connection between injection wells on (I think)

I seem to remember that some time in the 80's or 90's, (could have been earlier) that the FEDs finally made the connection between injection wells on (I think) haz-mat sites and tremors in Denver. The comparison between that and Ohio's current hold on fracking may or may not be related, but it does give one pause to speculate...