In February–March, 2023, a Working Group of 20 scientists from 10 countries met at the invitation of the International Agency for Research on Cancer (IARC) in Lyon, France, to finalise their evaluation of the carcinogenicity of four agents: anthracene, 2-bromopropane, butyl methacrylate (BMA), and dimethyl hydrogen phosphite (DMHP). Multiple studies showed that 2-bromopropane induced DNA damage in human leukocytes, micronucleus formation in rodents, and gene mutations in bacteria. Monograph Working Group Members RC Cattley (USA)–Meeting Chair; H Kromhout (The Netherlands); M Sun (USA); EJ Tokar (USA) –Subgroup Meeting Chairs; MA-E Abdallah (UK); AK Bauer (USA); KR Broadwater (USA); L Campo (Italy); E Corsini (Italy); KA Houck (USA); G Ichihara (Japan); M Matsumoto (Japan); S Morais (Portugal); J Mráz (Czechia); T Nomiyama (Japan); K Ryan (USA); H Shen (People's Republic of China); T Toyoda (Japan); KH Vähäkangas (Finland); MG Yakubovskaya (Russian Federation) Declaration of interests All Working Group members declare no competing interests Invited Specialists IJ Je Yu, Hyundai Calibration & Certification Technologies Co Ltd, Republic of Korea Declaration of interests IJY reports being an employee of HCT Co., Ltd., a former spin-off of Hyundai Electronics, whose work may involve competing interests for the topics covered at this IARC Monographs meeting Representatives C Dellavalle, National Cancer Institute, USA Declaration of interests CD declares no competing interest Observers G Tuschl, Methacrylate REACH Task Force (MRTF), Germany Declaration of interests GT is employed with Rohm GmbH, manufacturer of butyl methacrylate.