Laws aren't always rationally written, of course. A law intended to restrict thermal cameras could have the side effect of making "regular" IR films illegal even though that wasn't the original point.

But there just ain't no way to do analog IR photography without IR film. If it truly is illegal---not just thermal films, but SFX 200 and IR 820 and all the rest---then I think the OP is stuck with d*g*t*l.