（A question on toxicity PG for toxic substances.）
On the Declaration for shipping Division 6.1 Toxic substances, it showed PG I but in the “Additional Handling Information” box, there was an entry: “Packing Group by inhalation toxicity is PG II”. When checking the reason for this entry with the shipper, they described that the substance is Toxic PG I but for inhalation hazard, it would be PG II. Why would such a difference occur? Please enlighten us. (28 Feb 17)
Most probably, it is PG I by vapor inhalation toxicity. And by inhalation toxicity of dusts and mists, it is PG II. We will have to inspect their Material Safety Data Sheet to correctly determine the difference.