I don't know. It is good that it has been refrigerated, probably better had it been frozen. Sounds iffy.

I've taken DMSA that was maybe a year past the expiration date and that was stored in the freezer.

After the Obama administration stopped allowing DMSA to be available OTC I feared they would make it even more difficult to obtain. I purchased a larger then usual amount of it.

In contrast, I think a few years earlier, maybe during Bush Jr, they reduced the max OTC dose of Tylenol due to the liver damage but allowed doctors to prescribe higher doses. The lower doses of course continued to be available OTC.

They could have done the same for DMSA, for example, limiting the OTC to 50 or 100mg so stupid people would be less likely to take 1000mg for a provoked urine test.

Since Obama eliminated OTC DMSA entirely, maybe they were concerned that too many people were getting health gains from it and so might not be desperate for their communist health care system : ( That was certainly my very good experience from my years of lead detox with DMSA + ALA ( Cutler protocol ).

You can (and should!) google this - the US government, specifically the US military did a large study on a large number of drugs about just this topic. They store A LOT of drugs in case of conflict, a lot more than normally needed, so naturally they encounter this very problem on the scale of hundreds of millions of dollars of expired drugs.

They found that pretty much ALL drugs are safe to use long after expiration - 2 years is nothing in this context. There only were less than a handful of very specific drugs that were unsafe.

The only thing that will have happened is that there is a little less actual "DMSA" in your DMSA - but not much if you kept it refrigerated. I would not worry one bit about it in this context (they were refrigerated and it's DMSA, not a critical molecule).