Here are some key pieces of information from Sigma-Aldrich's MSDS for CAS: 2718-90-3.
- No known OSHA hazards.
- Not a dangerous substance according to GHS.
- Contains no substances with occupational exposure limit values.
DOT (US) - Not dangerous goods.
IMDG - Not dangerous goods.
IATA - Not dangerous goods.
I personally think this bodes very well for shipping overseas. Potassium dichromate on the other hand has a restriction in every category. So as far as any shipping entity cares, this stuff is no worse than table salt. It might be wise to check with individual country's regulations, but I think if we label the shipments "Screen Printing Ingredient", there shouldn't be a lot of interference.