The workers were 'exposed to' dangerous chemicals. [=they were placed in conditions that left them unprotected from dangerous chemicals]
His mistakes have 'exposed' him 'to' ridicule. [=he has been ridiculed because of his mistakes]
Children are being 'exposed to' violence on television.
(..) -Who is that? JOHN: If you can't outrun them... -I don't know. -...then you have one option. Their motor cortex is partially exposed at the back of their neck. A knife to this area will disorient their tracking device, but not for long. Above all, stay alive. You have no idea... (..)2009 Terminator Salvation