In a formal letter to the Nuclear Regulatory Commission, California Senators Dianne Feinstein and Barbara Boxer asked federal regulators to perform a \u201cthorough inspection\u201d of Diablo Canyon and San Onofre Nuclear Generating Station \u201cto evaluate their safety and emergency preparedness plans.\u201d The March 16 missive noted that \u201croughly 424,000 [people] live within 50 miles of Diablo Canyon and 7.4 million live within 50 miles of San Onofre Nuclear Generating Station. Although many safety measures have been taken to address potential hazards associated with these facilities, we need to ensure that the risk is fully evaluated.\u201d Greg Jaczko, commission chair, said that unlike Japan with a smaller evacuation zone, if a nuclear crisis arose in the U.S., an evacuation circle would extend for 50 miles around a troubled reactor. The senators also asked federal regulators to answer whether California\u2019s plants can be provided \u201cwith a greater margin of safety\u201d for earthquakes of greater magnitude than what\u2019s planned, and if new faultlines near those plants are under federal consideration. The next day, President Barack Obama asked for a review of the U.S.\u2019s nuclear facility safety. \u201cI\u2019ve asked the Nuclear Regulatory Commission to do a comprehensive review of the safety of our domestic nuclear plants in light of the natural disaster that unfolded in Japan.\u201d Obama stated March 17. In contrast to Obama\u2019s \u201cgeneral review,\u201d the senators\u2019 letter \u201cis asking specific questions\u201d about two California plants, noted Mary Kerr, Senate Committee on Environment and Public Works Committee spokesperson.