As purchasing power in China grows, their labour costs grow because they start demanding similarly unpolluted environment, and dirty production will start moving to the next country.
Is it not the answer that you demand a clean production or stop using products which cannot guarantee it? The fact that consumers do not apply this logic means that NIMBY can only take you so far, because if we accept polluting productions, some humans will have to deal with it somewhere.
I have a feeling factories will use H1B Visas to bring in immigrants to do the work and fire them as soon as the H1B Visa expires, and hire all new H1B Visa workers.