Philadelphia Water Department (PWD) has been conducting routine dye testing in neighborhoods near Henry Avenue and the Wissahickon creek. As a result, a bright green color may be seen in the water.

The dye used, Fluorescein, is a fluorescent compound commonly used in water tracing studies. It is non-toxic, safe for humans and wildlife, and considered harmless in the small quantities used by PWD.

The green color may be visible for up to three hours near the release site and will dissipate naturally.