irremediable

/ˌi(r)rəˈmēdēəb(ə)l/
adjective

1. impossible to cure or put right

“I am grateful it hasn’t been entirely destroyed,” Mr. Hall said. “But it was perfect, and now it’s –” The more he said the more he sounded angry. “The damage is irreversible, irremediable.”

– Cynthia Voigt, The Vandemark Mummy