According to a Safety4Sea article, DNV GL, together with marine insurers The Swedish Club, Norwegian Hull Club, Skuld and Gard have completed a study of the properties of environmentally acceptable lubricants (EALs) for stern tube applications, in response to the growing number of stern tube bearing failures recently.
Different Than Traditional Oil?In fact, DNV GL sponsored lab tests demonstrating that EALs behave differently than traditional mineral oils under transient pressure and temperature...
http://mfame.guru/eals-safety-margins-same-as-mineral-oil-finds-dnv-gl-study/