Are Duraflame Firestart logs safe to use indoors?

According to discussion in r/Fireplaces, the wax-and-sawdust composition burns cleanly enough that emissions go up the chimney in a normal fireplace, but several users in r/woodstoving and r/WildernessBackpacking note they burn dirtier than seasoned wood and can leave soot on cookware. They are designed as fire starters for open fireplaces and fire pits, not for cooking surfaces.