The executive who oversaw PG&E’s utility operation during the deadly San Bruno pipeline blast and the company’s turbulent aftermath will retire at the end of the year, company officials announced Tuesday. Christopher Johns, president of Pacific Gas and Electric Co., the utility wing of PG&E Corp., was hired in 1996 to help manage the utility’s finances. [...] it was his promotion to the electric company’s top job in 2009, a year before an exploding gas line killed eight people, that marked his tenure at the organization. PG&E officials said Johns was a committed leader who worked to achieve “international recognition for gas safety performance” for the company. The disaster resulted in a record $1.6 billion penalty for the utility, with state regulators citing PG&E’s shoddy record-keeping and reckless safety practices leading up to the blast. The utility has also been criticized for nourishing too cozy of a relationship with regulators at the California Public Utilities Commission.