44. Where the concentration of an ingredient in a controlled product or in a complex mixture that is a component of a controlled product is expressed as a percentage on the material safety data sheet, that percentage shall be determined as the ratio
(1) of the weight of the ingredient or mixture to the weight of the product,
(2) of the volume of the ingredient or mixture to the volume of the product, or
(3) of the weight of the ingredient or mixture to the volume of the product.
With any percentage concentration listed on the data sheet, it shall be stated on the basis on which of the foregoing ratios the percentage was determined.
That percentage may be expressed by reference to the range of concentration within which the ingredient or mixture falls, rather than its actual concentration.
The reference ranges of concentration are
0.1 to 1%
0.5 to 1.5%
1 to 5%
3 to 7%
5 to 10%
7 to 13%
10 to 30%
15 to 40%
30 to 60%
40 to 70%
60 to 100%
The concentration of an ingredient may also be expressed by reference to the subranges of concentration included within a reference range of concentration.