Your containership has a container displaying a hazardous cargo placard. The placard has the number 2199 on it. This indicates that it is carrying what cargo?

Correct Answer: Option D — Phosphine

Under the 49 CFR 172.101 Hazardous Materials Table, UN number 2199 specifically designates phosphine, an extremely toxic and flammable gas requiring strict containment and hazard communication placards.