Before striking a pipeline, causing a natural gas leak and subsequent explosion, an engineering firm did follow proper protocol to begin work at a Dallas apartment building.

An investigation led by the National Transportation Safety Board is still underway to answer questions about what went wrong.

Sparse but chilling details show the firm overseeing a soil analysis at the site of a deadly Oak Cliff apartment explosion reported a drilling company damaged a gas line near the building.

Dallas Fire Chief Justin Ball says everyone who lived at the apartment building destroyed by a natural gas-fueled explosion on Thursday has been accounted for. Ball confirmed Friday that three people ...