Nylon

Nylon's specific issue is oligomers: short cyclic chains left over from polymerisation that migrate into food. Germany's BfR measured 33 polyamide kitchen utensils and found total PA 6 and PA 6,6 oligomer transfer of 0.94 to 10.87 mg per kg of food (median 2.81), with 10 of the 33 above the 5 mg/kg group migration value BfR considers toxicologically acceptable. The oligomers themselves tested non-genotoxic, and BfR judged health impairment unlikely below that value. Separately, polyamide kitchenware imported from China and Hong Kong has released primary aromatic amines - a family that includes carcinogens and suspected carcinogens - at levels that led the EU to require per-consignment testing under Regulation (EU) No 284/2011, against a detection limit of 0.01 mg/kg. The 2024 finding of brominated flame retardants in black recycled-plastic utensils is real but was badly over-read: the authors corrected their exposure arithmetic twice, and the revised BDE-209 intake estimate of 7,900 ng/day sits far below the US EPA reference dose of 420,000 ng/day. The concentrations measured in some black utensils still stand. They are an argument for knowing the feedstock, not for throwing out the drawer.

Migration from nylon is a function of temperature and contact time together. BfR ran its utensil tests at 100 °C for 30 minutes to 2 hours - conditions the EU treats as representative of use between 70 and 100 °C - and concluded that substantial oligomer transfer can occur above 70 °C, recommending that contact with hot food be kept as brief as possible. Note the wording: BfR sets no permitted contact time, so the widely repeated "15 minutes" rule is not theirs and should not be quoted as if it were. The practical reading is to stir with a nylon utensil and take it back out, rather than leaving it resting in a simmering pot.

A nylon utensil is rigid and taps hard; silicone of the same shape bends and thuds. Against polypropylene, nylon is harder, glossier and denser - it sinks where PP floats. On clothing, read the fibre-content label: European labels usually say polyamide, US ones nylon, and both mean this page. Black kitchen tools are the case worth pausing on, because black is the colour recycled electronics feedstock ends up in and optical sorters cannot see. If a brand will not name the resin, ask three things: which polyamide (PA 6 or PA 6,6), virgin or recycled feedstock, and whether they hold migration test data for oligomers and primary aromatic amines.

Nylon absorbs water, which is why utensils stain, swell slightly and lose gloss over time. Repeated dishwasher cycles combined with hot oil discolour and eventually embrittle it, and brush bristles splay and take a permanent set. A utensil with a melted edge, deep score marks or a chalky surface has more exposed area in contact with hot food than a new one, so it is worth replacing rather than nursing.

Nylon 6 is one of the few textile plastics with a genuine commercial chemical-recycling route, used for regenerated fibre from fishing nets and carpet, but that route needs clean sorted industrial feedstock. Nothing about it applies to a household spatula or a cotton-and-nylon garment. No curbside programme accepts nylon items, and the polymer does not biodegrade.