Per the AAMVA CDL Manual, what is the maximum amount of solid Class 6 poison a bus may carry?

AAMVA CDL Manual Section 4.2.2 "Forbidden Hazardous Materials," p. 4-2

Bus drivers are responsible for knowing exactly which hazardous materials, and how much of them, can legally ride with passengers. Getting this wrong risks a hazmat incident in an occupied vehicle with no easy evacuation, and it's one of the specific numeric limits the real CDL passenger endorsement exam tests.