Class 6 has a special rating system for Poison gases, how are they labeled?

• A. PG II, PG I, PG III
• B. PG I, PG II, PG III
• C. PG I, PG III, PG II
• D. PG II, PG III, PG I

Answer: (B)

Poison gases are categorized into three levels to show how toxic they are, guiding how strictly they must be handled. PG I indicates the most dangerous gases with the strictest controls, PG II indicates toxic gases with substantial hazard, and PG III indicates gases that are toxic but less so. The labeling is arranged from most hazardous to least: PG I, then PG II, then PG III. That makes the sequence PG I, PG II, PG III the correct one, since it accurately reflects the increasing safety margins and required precautions. The other sequences would misrepresent the relative hazards and could lead to insufficient protections for the more dangerous gases.