A New Orleans court has found chief engineer Warlito Tan not guilty of four felony counts including pollution and obstruction of justice.

It is a rare win for a defendant in a US pollution case, and one in which federal judges rejected some of the prosecutors’ requests for subpoenas of crew members as “unreasonable and oppressive”.

The full acquittal for Tan, formerly of the 33,700-dwt Joanna (built 2010), comes despite a guilty plea by manager Empire Bulkers and registered owner Joanna Maritime on parallel charges.