<P> The United States Environmental Protection Agency ( EPA ) outlawed the use of fluorescein for this purpose , since it was shown to be harmful to the river . The parade committee has since switched to a mix involving forty pounds of powdered vegetable dye . Though the committee closely guards the exact formula , they insist that it has been tested and verified safe for the environment . Furthermore , since the environmental organization Friends of the Chicago River believes the dye is probably not harmful , they do not oppose the practice . </P>
<P> The United States Environmental Protection Agency ( EPA ) outlawed the use of fluorescein for this purpose , since it was shown to be harmful to the river . The parade committee has since switched to a mix involving forty pounds of powdered vegetable dye . Though the committee closely guards the exact formula , they insist that it has been tested and verified safe for the environment . Furthermore , since the environmental organization Friends of the Chicago River believes the dye is probably not harmful , they do not oppose the practice . </P>
how do they make the chicago river green
how do they make the chicago river green
forty pounds of powdered vegetable dye
forty pounds of powdered vegetable dye