The imminent move to label aspartame as a possible carcinogen comes after years of advocacy from a leading consumer group in the United States and a handful of cancer scientists hoping to settle a decades-long debate over the sweetener's safety. Reuters reported last month that the cancer research arm of the World Health Organization (WHO), known as the International Agency for Research on Cancer (IARC), was set to make that declaration on July 14, according to two sources with knowledge of the process. The designation as "possibly carcinogenic to humans" will provide an incentive to fund more rigorous research into the safety question, toxicology and cancer experts say.