#Ansonia CT–cttraffic–Route 8 northbound was closed for over 14 hours Thursday.  State Police  say Chris Roche, 38, of Bayberry Road in Fairfield was found to be at fault for the accident .  Connecticut Tank Removal was called to the scene for the hazardous removal of of iso-cyanate derivatives which can cause lung and liver damage if not properly handled.  It is used to make foam insulation, in paint and in a protective coating to line truck beds .  Police say Roche was traveling in his Ford F-250 pickup, pulling a 24-foot enclosed box trailer when he swerved from the right lane and struck the metal guard rail at the side of the highway.   He then crossed over and crossed over to the left lane hitting the cement barrier in the median, spilling the 55-gallon drum barrels.   The chemical then froze during clean up and had to milled off the highway.  Roche will be billed for the clean up, milling and paving of the highway.  Special thanks to Connecticut Tank Removal for these photos.