Many of my recent paintings have been done on MingART paper from China. They have several different surfaces–all of which are great for different pastel techniques.
The question arose recently as to whether or not these were acid-free and non-toxic. The marketing materials for the paper currently do not specify the answer.
The short answer is YES: MingART papers are acid-free and non-toxic.
The email I received from the company today included a complete report showing that MingART papers were certified in 2017, having passed the ASTM D-4236 and TRA tests.