LONDON, June 29 (Reuters) - One of the world's most 
    common artificial sweeteners is set to be declared a 
    possible carcinogen next month by a leading global health 
    body, according to two sources with knowledge of the 
    process, pitting it against the food industry and 
    regulators.

    The IARC's decisions have also faced criticism for 
    sparking needless alarm over hard to avoid substances or 
    situations. It has four different levels of 
    classification - carcinogenic, probably carcinogenic, 
    possibly carcinogenic and not classifiable. The levels 
    are based on the strength of the evidence, rather than 
    how dangerous a substance is.

IARC is only nominally under WHO. It is a weird French agency founded by some French activists and politicians in the 1960's.

They use a 5 class classification

    Group 1: The agent is carcinogenic to humans.
    Group 2A: The agent is probably carcinogenic to humans.
    Group 2B: The agent is possibly carcinogenic to humans.
    Group 3: The agent is not classifiable as to its carcinogenicity to humans.
    Group 4: The agent is probably not carcinogenic to humans.

For IARC, everything is either at least possibly carcinogenic, or there is insufficient evidence (Group 3) to yet declare it carcinogenic.

Also:

"In 2019 IARC was accused of cooperation with "toxic tort law firms" who make profit of suing companies for compensation for alleged health issues based on IARC classification. IARC was accused from hiding conflicts of interest impacting a few invited experts, especially those related to large-scale cash flows from US law firms."

https://en.wikipedia.org/wiki/International_Agency_for_Resea...

Many countries have perfectly capable chemicals agencies and food safety agencies, who are much more reliable than the IARC.