We now know the substance found in the Boise River near the Americana Bridge on Wednesday was red dye used to test equipment at a local dairy company.
A spokeswoman for the Boise Fire Department did not identify the company, but says the substance is not toxic.
She says the dye was supposed to be disposed of through a sewer pipe but somehow ended up in a storm drain.
ACHD crews pumped the substance out of the storm drain. At this point they aren't sure how much of the substance made it into the water.
Hazmat crews and firefighters were called to the scene around 5 p.m. on Wednesday after somebody spotted the red substance in the river.