A 44-year-old woman and her young daughter are among those feared dead after a massive explosion ripped through a Northern California neighborhood.

Officials have confirmed that four people were killed Thursday night when a gas line ruptured in San Bruno and a fireball exploded through a group of homes. They have not released any names.

Agustin Macedo of San Francisco told The Associated Press on Friday that his 44-year-old daughter, Jacqueline Greig (GREEG), and his granddaughter were killed. Reached by phone, Macedo said he was too upset to give any more information, including how he knew his family members' fate. The granddaughter's age and name weren't known.

Greig lived in a house just yards from the source of the blast.

Greig worked at the California Public Utilities Commission. Executive Director Paul Clanon announced to staff Friday morning that Greig was missing.