I’m sure.
We pay them. They put it on barges, take it out to sea, and dump it in the ocean.
Actually, they can't.
The Coast Guard makes a living off of auditing the vessel logs to track everything from cargo, to spent oil discharge, garbage burn logs, etc. CBP does the same thing, but not with the thoroughness of the Coasties.
I once ran into a captain of a Chinese vessel that had violated all these protocols, was facing 5 years in prison, and likely, when he returned to the loving care of the Chi-coms, a bullet in the head.