SeaWorld was accused of giving its whales psychoactive drugs similar to Valium in order to control their behavior.
The information was revealed in a sworn statement from former vice president of SeaWorld Dr. Lanny Cornell, according to the Daily Mail.
A spokesperson for SeaWorld said the medication is used to sedate the animals for medical procedures and to control seizures, according to the Daily Mail. It is prescribed by a veterinarian and regulated.
Animal activists called the drug the “final straw,” noting prolonged use may cause panic attacks, out-of-body experiences and muscle spasms.
SeaWorld faced a slew of criticism after the documentary “Blackfish” was released in 2013.
It portrayed life in captivity and examined the treatment of the whales.