An hours-long cleanup of an unknown substance on the 210 Freeway caused a lengthy backup of traffic in Pasadena on Monday evening.
The work began at around 3 p.m. on westbound lanes of I-210 near Lake Avenue, according to the California Highway Patrol, who issued a SigAlert due to the cleanup.
Though they only expected the road to be closed for around two hours, the closure extended well past 7:30 p.m., with the two rightmost lanes still closed…