NICNAS attended two international meetings addressing specific risk assessment methodology issues: an OECD Taskforce meeting on Environmental Exposure Assessment and a WHO IPCS Workshop on Skin Sensitisation in Chemical Risk Assessment (held 20-21 September and 17-18 October 2006 respectively). The skin sensitisation workshop addressed issues of adequacy of available knowledge on skin sensitisation and experimental test methods for assessing risk, as well as the potential development of the Local Lymph Node Assay (LLNA) for chemical risk assessment.