The US Food and Drug Administration is proposing to let companies add certain chemicals directly to food without a safety review by widening an existing exemption.

Currently, the exemption covers chemicals used in food packaging or processing equipment if they are not carcinogenic and their levels remain below 0.5 parts per billion. The proposed expansion could cover flavourings, preservatives, emulsifiers and other ingredients added to food.

Campaigners say some chemicals, particularly hormone disruptors, may pose risks at concentrations well below that limit. An existing exemption allowing perchlorate in grain bags sharply increased the amount found in children’s cereal; advocates say the chemical could cause brain damage.

The expansion is part of a proposed rule concerning a separate food-safety exemption that the FDA and Robert F Kennedy Jr said in August they were closing.