H2SO4 = There are reports for cell proliferation at tunica mucosa laryngitis within range of category I by 28 days respiration exposure test by Ra+SIDS(2001)
Hyperplasia of bronchiole cell at lungs within range of categoryI
By respiration exposure test by Macaca fasciculars
(0.048 mg/L, 23.5 hr/day, ATSDR 1998)