ST. LOUIS (AP) — The children of a woman who was among four people killed when a steam-filled tank weighing nearly 2,000 pounds (900 kilograms) exploded at a St. Louis box plant and flew onto a building are suing the plant.

Online court records show that Tonya Gonzalez's children, Nathan and Nicole Favignano, filed the wrongful-death lawsuit last week in St. Louis Circuit Court against Loy-Lange Box Co. and five other companies.

The April 3 explosion inside the Loy-Lange plant killed a worker there. The tank then flew into nearby Faultless Healthcare Linen, killing Christopher Watkins, Tonya Gonzalez-Suarez and Clifford Lee.

Watkins' father and sister, as well as seven Lee siblings and one of his brothers, already are separately suing Loy-Lange over the blast.

Loy-Lange declined to publicly comment Thursday.