Table 2.

Overview of assessment tiers, outlining the composition of each in relation to methodologies incorporated

Assessment tier	Approach overview	Methodologies incorporated	Category assignment
0	Cramer classification	Cramer scheme (with extensions)	Classification-category probability distribution (Table 5)
1	In silico	EPA TEST LD50	Bayesian model
		Random forest LD50
		Structural alerts
2	In vitro	In vitro cytotoxicity (cell viability assay)	Bayesian model
3 (hypothetical)	In vivo	OECD Test Guideline 425: Acute oral toxicity	Experimental outcome