California officials have ordered an emergency shut-down of 11 oil and gas waste injection sites and a review more than 100 others in the state’s drought-wracked Central Valley out of fear that companies may have been pumping fracking fluids and other toxic waste into drinking water aquifers there.

http://www.propublica.org/article/ca-halts-injection-fracking-waste-warning-may-be-contaminating-aquifers