Pacific Gas and Electric Co. adequately marked its underground infrastructure at the site of a gas explosion that burned five buildings and sent people running for their lives in San Francisco’s Jordan Park neighborhood, the company said Thursday. A PG&E locator responded to the site near Geary Boulevard and Parker Avenue on Jan. 28 and properly marked the utility’s underground lines there, capturing the work with photography, according to PG&E spokeswoman Andrea Menniti. California law gives PG&E two days to respond to excavators’ requests to locate and mark its underground pipelines, unless the two parties mutually agree on a different timeline.