A Houston-based law firm secured a settlement of $18 million in state district court after two parents sued an apartment complex when their young son drowned in the swimming pool on the property.

The amount was the largest settlement or verdict ever made for a single child drowning case in U.S. history, according to a verdict analysis the parents’ attorneys conducted. Their lawyers argued that the facts of the case made the complex’s owners and management more liable than in any previous, similar lawsuit.