A systematic review of herbicide safener toxicity

Abstract

Herbicide safeners are agrochemicals added to herbicide formulations to protect crops from herbicide damage without reducing the effectiveness of the herbicide against weeds. While safeners are typically structurally similar to their co-formulated herbicides, they are classified as "inert" in the United States, meaning they are not held to the same regulatory standards as the herbicides. This review systematically examines the toxicity of safeners, which is important given their large-scale global use and potential for exposure to wildlife, livestock, and humans. A systematic review of peer-reviewed literature identified only seven studies examining safener toxicity. Regulatory toxicity data, compiled from the European Chemicals Agency (ECHA) database, included data for 9 of the 18 commercial safeners. Most safeners have low acute ecotoxicity and mammalian toxicity; however, chronic effects and the underlying mechanism are less clear. Benoxacor showed enantioselective metabolism and depletion by drug-metabolizing enzymes. In conclusion, despite the widespread use of safeners, significant knowledge gaps exist regarding their toxicity. More research is needed to fully characterize the potential risks of safeners to human health and the environment. Regulatory agencies should consider reclassifying safeners as active ingredients to ensure adequate toxicity testing and risk assessment.