Thyroid hormones regulate cellular energy metabolism throughout the body and chemical disruption of this function in humans causes neurological, hearing, and vision dysfunction in children, as well as metabolic disorders and cancer in adults. Due to the complex nature of the thyroid system, the way many Superfund chemicals disrupt thyroid function is unclear. We propose to bioengineer thyroid and liver microtissues and use them along with computational modelling to understand how these chemicals cause toxicity, test chemicals and their mixtures for their ability to disrupt thyroid signaling, and translate our findings to determine how chemical exposures might affect human populations.