MANDAN, N.D. - The children of a couple who were killed in a Morton County home explosion in December 2016 have filed a lawsuit against a local energy cooperative and propane supplier.

The home explosion, which was blamed on a propane leak, rocked an entire neighborhood north of Mandan on Dec. 14, 2016. The explosion killed Clyde and Elizabeth Howe, and left Elizabeth Howe's daughter, Elianna Vazquez, severely injured.

The couple's six children, including Elianna Vazquez, filed a lawsuit against Tri-Energy Company and CHS Inc., in October. The lawsuit seeks an unspecified amount of monetary damages.

Clyde and Elizabeth Howe's home, located off N.D. Highway 1806, about 5 miles north of Mandan, exploded early Dec. 14, 2016. The blast was reported by a neighbor, who said it caused his house to shake.

Elianna Vazquez suffered from a broken back, six broken ribs and a collapsed lung due to the explosion. She spent several days at CHI St. Alexius Health in Bismarck, where doctors fused together her shattered lower spine.

The lawsuit alleges that Tri-Energy Cooperative, which is headquartered in Bismarck, failed to install a "second-stage propane regulator consistent with recognized safety standards."

The regulator was damaged from heavy snow and ice that fell from the roof of the house, and thus caused the explosion, the lawsuit says.

Ashlee Sherrill, a spokeswoman for the Bureau of Alcohol, Tobacco, Firearms and Explosives, said in 2017 that a buildup of snow outside the house caused the regulator to malfunction.

The lawsuit also claims that the propane had not been odored, which is done to alert people of leaks.

The lawsuit names CHS Inc., formerly called Cenex Harvest States, which it says supplied propane and propane equipment to Tri-Energy Cooperative.

John Radmer, an attorney for Tri-Energy Cooperative, declined to comment on claims made in the lawsuit, but said "Tri-Energy is sympathetic to the plight of the Howe and Vazquez families, but we have no reason to believe that Tri-Energy has any responsibility for the Dec. 2016 incident."

In court documents, attorneys for CHS Inc., also denied that the company is at fault.

The lawsuit includes counts of negligence, breach of warranty, strict liability, and negligent selection, hiring, supervision and retention.

Jeffrey Weikum, an attorney for Elianna Vazquez, did not respond Wednesday to a request for comment.

A jury trial for the case is scheduled for Oct. 28, 2020, to Nov. 6, 2020.