Table 1.

Examples of application of the WOE approach in HASPOC's decision-making process – considerations for a subchronic inhalation study waiver.

Pesticide		Chemical A	Chemical B
WOE considerations	Toxicity Profile	Low acute inhalation toxicity (no pulmonary effects up to limit concentration)	Acute inhalation toxicity studies showed pulmonary lesions
	Physical/chemical properties	Low vapor pressure and Henry's Law constant-not expected to volatilize	Low vapor pressure and Henry's Law constant-not expected to volatilize
	Use and exposure patterns	Potential for short- and intermediate-term occupational inhalation exposure	Potential for short- and intermediate-term occupational and short-term residential inhalation exposure
	Margins of Exposure (MOEs)	Inhalation MOEs: 13,000–25,000,000 (> 10X the level of concern [LOC] of 100) using an inhalation point of departure (POD) selected from an oral study	Inhalation MOEs: 130–28,000 (4 scenarios below 10X the LOC) using an inhalation POD selected from an oral study
	Information from chemical class or structurally-related pesticides	No structurally related pesticides with inhalation information identified	No structurally related pesticides with inhalation information identified
	Risk assessment implications	An inhalation study is not expected to provide PODs to change the overall risk picture	An inhalation study may provide more sensitive PODs for risk assessment than the oral studies
HASPOC Recommendation		Inhalation study can be waived	Inhalation study is needed