Richmond Hill neighborhood (wibc.com photo by Mike Corbin)

Officials estimate damage caused by an explosion late Saturday night on the Indianapolis South side will cost around $3.6 million.

The blast killed two people. Two-hundred others were checked for injuries. The Indianapolis Fire Department (IFD) says four homes were fully engulfed when they arrived. The blast damaged homes within a two block radius.

The city's Department of Code Enforcement (DCE) told the media Sunday afternoon that inspectors have been through all 126 homes in the Richmond Hill neighborhood. Inspectors determined five homes were destroyed or suffered enough damage to require demolition. They say 26 more homes had damage major enough that they are unsafe for occupants. Another 50 homes had minor damage. Any Richmond Hill residents with questions about the status of their homes should contact DCE at (317) 327-8454.

IFD says investigators have not yet ruled out any potential causes of the explosion. Several agencies and Citizens Energy are now part of the investigation, including the Department of Code Enforcement and IFD arson investigators. Congressman Andre Carson says the National Transportation Safety Board and Department of Transportation are also en route and will investigate due to their jurisdiction over the gas lines.

Citizens Energy says a gas leak detection survey in the area did not find any leaks. Spokesman Dan Considine says Citizens Energy did not receive reports of suspicious odor or other concerns before the explosion. He says most of the time, but not always, people can smell a gas leak due to the odor that is added by the gas company. Considine says 30 homes in the area are still without gas as of Sunday afternoon.