Aspartame will be declared a possible carcinogen by the World Health Organization’s cancer research agency, according to a report. The substance—which is one of the most commonly used artificial sweeteners replacing sugar in food and beverages including diet sodas—will be considered “possibly carcinogenic to humans” for the first time by the International Agency for Research on Cancer (IARC), Reuters reports. The news agency cited two sources familiar with the process as saying that the IARC’s ruling was finalized earlier in June following a meeting of the group’s external experts and is intended to determine if something is a possible hazard based on all available published evidence.