Natural gas is the suspected source of a massive house explosion in Lincoln, Nebraska that critically injured two people yesterday afternoon. The blast, which occurred near the intersection of 77th Street and Old Cheney Road around 4:30 p.m., was so powerful that it leveled the home and damaged at least 42 others.

Neighbors rushed to help Jim and Jeanne Jasa who were inside the home at the time of the explosion, carrying them to safety and performing first aid until emergency responders arrived on the scene, The Jasas sustained life-threatening injuries including third-degree burns and are in critical condition at CHI St. Elizabeth Hospital.

Residents five blocks away felt the vibrations of the explosion which scattered debris in a 200-foot radius and shattered the front windows of a house located one block away. Of the 43 homes that were damaged, 19 sustained structural damage and three are uninhabitable. Some of the homes were shifted off of their foundations.

Sonic boom, airplane crash, tornado is how witnesses described to local newspapers and television crews the sound of the explosion. Lincoln’s Public Safety Director Tom Casady told KLIN-AM radio that a house explosion of this magnitude had never occurred during his tenure.

Neighborhood residents said energy crews had been doing underground work nearby. Officials have not yet determined the source of the blast. A team from Black Hills Energy is working with investigators from the state Fire Marshall’s office. Chief Fire Inspector Bill Moody told radio station 10/11 that all digging permits issued in the last six months would be reviewed as they try to determine the cause of the blast.

In June, an explosion of similar size occurred in Marengo, IL.  Two people were injured in that explosion which damaged 50 homes.