An hours-long cleanup of a hazmat spill reported late Sunday on northbound Interstate 805 has caused a major backup on the freeway Monday. As of 8:50 a.m., two lanes were open just north of Clairemont Mesa Boulevard, a California Highway Patrol spokesperson said. Three lanes of the freeway were blocked after a crash was reported south of state Route 52 shortly after 11:30 p.m., Caltrans San Diego reported on social media. About eight gallons of engine oil spilled as a result of the crash and hazmat crews were working to clean up the freeway lanes, the CHP spokesperson said. Caltrans maps showed very slow speeds on north I-805 starting south of Interstate 8 all the way up to the incident location.