The National Transportation Safety Board has launched an investigation into a natural gas explosion that destroyed a home and injured six people Thursday near Hayward.

The neighborhood remained closed off Friday morning, and the Alameda County Fire Department was still at the scene along Lewelling Boulevard.

There has been ongoing construction along the roadways in the unincorporated area known as Ashland, and it could be related to Thursday's explosion. A neighbor’s surveillance camera captured the eruption just after 9:30 a.m.

Fire officials believe three of the injured people were inside the home or homes, and three work for PG&E. Officials from the NTSB will join PG&E in the investigation.

Preliminary information from PG&E and fire officials indicate at 7:35 a.m. Thursday, a third-

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