In the United States, chlormequat is classified as a low risk
plant growth regulator and it is registered for use on ornamental plants grown in greenhouses, nurseries, and shadehouses. The (rat, oral) is approximately 670 mg/kg. Chlormequat has not previously been registered for use on food crops in the United States. In April 2023, the
U.S. Environmental Protection Agency proposed allowing the use of the chemical on food crops such as
barley,
oat,
triticale, and
wheat. The EPA's human health risk assessment indicated "no dietary, residential, or aggregate (i.e., combined dietary and residential exposures) risks of concern." No risks were identified by EPA to aquatic species of invertebrates, vertebrates, and plants in addition to terrestrial plants.
EU Regulations In July 2022, the EU published Regulation (EU) 2022/1290, which amended the maximum residue levels (MRLs) for chlormequat in or on certain products, based on the scientific assessment of EFSA and the international standards of the
Codex Alimentarius Commission. The regulation lowered the MRL for chlormequat in citrus fruits from 2 mg/kg to 0.5 mg/kg, and also modified the MRLs for other products such as apples, pears, quinces, cherries, plums, apricots, and barley. The regulation also set a specific MRL of 0.01 mg/kg for Spodoptera exigua multicapsid nucleopolyhedrovirus (SeMNPV) isolate BV-0004, a biological plant protection product containing chlormequat as a co-formulant. The regulation entered into force on 14 August 2022. ==References==