Photo courtesy Gothamist reader Heather D. One Park Slope resident emailed us to describe a surprising scene unfolding this morning on 4th Street between 6th and 7th Avenues.I went out for my coffee around 10am and there were 4 white undercover SUVs, an NYPD emergency truck and a large, black DEP/HAZMAT truck/mobile unit parked on my street! When I came back from my coffee run I saw a Fire Dept. SUV parked at the 6th......