(KRON) — A Menlo Park road has been shut down due to a hazmat situation Thursday evening, according to the Menlo Park Police Department (MPPD). The public is asked to avoid the 1300 block of Henderson Avenue.

An “unknown green substance” was found at a residence on that street after homeowners were cleaning out the house, MPPD said. Out of an abundance of caution, a hazmat team was summoned to find out what the substance was.

As of 8 p.m., the street remains blocked, and it is unknown what the substance was. Police said no shelter-in-place orders were issued.

Menlo Park police sent out a Nixle alert at 5:52 p.m.

This is a developing story. Check back as KRON4 learns more.