Table 3.

Incidence of MnSO₄-induced microscopic lesions observed in young male rhesus monkeys exposed to MnSO₄. Incidence is expressed as number affected/number examined.

Lesion	MnSO4 exposure concentration (mg Mn/m3)	15	33	Exposure Day 65	65 [+45]a	65 [+90]a
Subacute bronchiolitis/alveolar duct inflammation	0			0/6
	0.06			0/6
	0.3			1/4b
	1.5	3/4*	4/4*	3/4*	0/4	1/4
Increased bronchus associated lymphoid tissue	0			0/6
	0.06			0/6
	0.3			1/4
	1.5	2/4†	3/4*	1/4	2/4†	1/4

^a Number in brackets indicates number of days post exposure assessment

^b Subacute bronchiolitis was observed in one monkey; however, in this animal only, this lesion was observed in conjunction with aspirated food particles.

* p < 0.05 (Pearson's chi-square test)

^† p = 0.053 (Pearson's chi-square test)