PCL has not evaded marine plastic surveys despite its current, more specialized uses. Of concern is that alkali hydrolysis of PCL has been shown to result in more bioactive PCL nanoparticles. Because seawater is alkaline (pH ~8.1), this implies potentially more adverse impacts from PCL degrading in marine environments than others. Moreover, large-scale resin pellet spills have become more common, which is superimposed on a well-recognized baseline of endemic resin pellet pollution from industrial practices. As we have shown for one species of fish and others for primary producers, PCL pellets can potentially harm a range of aquatic organisms. In light of our findings, a spill of PCL pellets in or near a waterbody is worrisome, suggesting the need for legislation and accountability to prevent resin pellet spillage.