An unknown substance caused 26 employees at a San Francisco recycling facility to become ill this morning, including two who had to be hospitalized.

The incident began around 7:30 a.m. at Recycle Central at Pier 96, located at 1000 Amador St., according to fire officials.

SEE RELATED: 2 hospitalized, 26 ill in hazmat situation at SF Recology center

Employees at the recycling facility, which is operated by Recology SF, reported feeling ill after handling trash and other recycling material, fire officials said.

Recology SF officials believe that a hazardous household product that was thrown into a recycling bin is to blame, although the exact product is still under investigation, Recology SF spokesman Eric Potashner said.

Most of the employees who fell ill were treated at the scene. The two who were hospitalized suffered injuries not considered life-threatening, Potashner said.

After arriving on scene, fire officials confirmed this morning that the incident was not a threat to the public.