If the chemical industry is to profit from refining waste crustacean shells and other by-products of seafood processing, collection problems and food-safety issues need to be overcome (see N. Yan and X. Chen Nature 524, 155–157; 2015).

Gathering sufficient animal feedstock for commercial purposes will be a formidable challenge (R. L. Naylor et al. Proc. Natl Acad. Sci. USA 106, 15103–15110; 2009). The transport and storage of seafood by-products from different processing plants is also likely to be extremely costly.

Moreover, expensive energy-intensive drying of crustacean shells would be necessary to prevent microbial growth and production of carcinogenic bacterial aflatoxins. Other health risks could arise from bioaccumulation of contaminants (such as heavy metals in shells) or from cross-species transmission of pathogens and perhaps even of prions through the food chain (L. Cao et al. Science 347, 133–135; 2015).