OMYA's biocides are classified as "pesticides" by the state of Vermont
Within the "pesticide" classification, they fall under the "Cooling Tower" category

Cooling Tower Pesticides used in Rutland County in 2000
in Pounds of Active Ingredients

2-Methyl-4-isotiazolin-3-one	84.35
5-Chloro-2-methyl-4-isothiazolin-3-one	277.14
Dazomet	90,767.37
Sodium O-phenylphenate	73,155.80
Sodium hypochlorite	162,877.00
TOTAL	327,161.66

Data from Vermont Department of Agriculture
October, 2001