The shipping industry is warning of uncertainty and confusion when a global push for cleaner fuel hits New Zealand. Marpol, which is short for marine pollution, is an international convention created to prevent pollution from ships. The Government is consulting on whether it should sign up to the sixth part of the agreement, reducing air pollution and lowering carbon emissions. But those in the industry say the change will make it hard for shipping operators to know if the right fuel will be available at foreign ports. Laura Dooney reports.