We have been advised that the state water police in Bremerhaven are checking ship's oil record books regarding handling of waste oil products, and that they appear to be particularly concentrating on engine sludge.
They work on the basis that sludge is generated at a certain (generous) rate and if the oil record book does not show that quantity of sludge has been properly disposed of they take this as evidence that, at best, the ship has not properly recorded the disposal of the sludge, or possibly the ship has been improperly disposing of the sludge.
It has been noted that ships which incinerate their sludge often forget to record this.
Failing to keep proper records is itself an offence rendering the ship and crew liable to penalties, with a possible delay until suitable guarantees are provided that fines will be paid.
Source of information: Trevor Elliston through Bill Kirrane E51