Citing increasing use of what they call risky practices when boats haul oil across Puget Sound, environmentalists are making a bid for a new law regulating marine vessels to match 2015’s stricter controls on the boom in oil transport by railroads. But they may have reached their high-water mark for action by the 2015-16 Legislature.

Scientists say Puget Sound — in failing health for decades and beset by a litany of insults, including toxic pollution and shoreline development — could be dealt an ecological death blow by an oil spill in its poorly flushed waters. Think of it like drowning a person who already had been dying of the proverbial thousand cuts.