There are a lot of details, but I’ll try and cut to the chase.
IARC is an agency within the WHO that conducts and coordinates research into the causes of cancer. In addition, they assess the “hazard” of products...is harm POSSIBLE”. The EPA, who assesses “risk” (is harm LIKELY), disagrees with IARC. On April 30 of this year, they reaffirmed that gly doesn’t cause cancer. Many regulatory agencies in other countries agree with the EPA. Now, back to IARC. Because they are assessing risk, the majority of substances they’ve looked are indeed classified as probably carcinogenic. To put it into perspective, they have reviewed almost 1000 substances in over 40 years of work. Do you know how many they DIDN’T find to probably cause cancer? Uno. One.

Outback, I have not seen any case where mixing gly and imazapyr was an issue. It all depends on what you are trying to do. Kill cogongrass? Many people mix the two. Spraying underneath your fenceline? Probably would leave the imazapyr out.

If you do the things you need to do when you need to do them then someday you can do the things you want to do when you want to do them.