(AP) -- The letter sent Wednesday to Gov. Jerry Brown comes after California adopted regulations requiring oil companies to test groundwater and disclose chemicals used in fracking.
The group said the strict new rules, which become permanent in 2015, will ensure fracking is done responsibly.
The scientists include Stephen Holditch, a petroleum engineering professor emeritus at Texas A&M University, and Richard Muller, a physics professor at the University of California, Berkeley.
The letter follows one by top U.S. scientists urging a fracking moratorium, saying the process increases pollution and runs counter to California's greenhouse gas reduction efforts.