(4)Nothing in this section applies to any case in which the ballast or rubbish or such other thing is cast or thrown into, [or the oil or water mixed with oil is discharged in or into] [Inserted by Act 39 of 1923, Section 3.], any such port with the consent in writing of the conservator, or within any limits within which such act may be authorized by the [Government] [Substituted by the A.O. 1937 for "Local Government"].
