So, it turns out that most of the red pigment in B.49 was made out of cinnabar. From wikipedia:
Because of the high toxicity of mercury, both the mining of cinnabar and refining for mercury are hazardous and historic causes of mercury poisoning. In particular, the Romans used convict labor in their mines as a form of death sentence. The Spanish also used shorter term convict labor at the Almadén mines, with a 24% overall fatality rate in one 30 year period.