How old your ranitidine would have to be to have too-high NDMA level without higher heat, I haven't seen any specifics around that.

I imagine they could have instead instituted limits about temperature of storage and transport, and chop down the expiration dates, and add big warnings for consumers to actually respect the dates, not keep them in cars, etc... though the market reality that there are several other H2 blockers out there that haven't been shown to have the NDMA issue, not to mention PPIs, likely meant that just pulling ranitidine was the better call.