Mammoth Uncensored Word List:
16 words ending with el, 13 letters long

antipersonnel attobecquerel cockerspaniel decabecquerel decibecquerel gigabecquerel kilobecquerel megabecquerel nanobecquerel petabecquerel picobecquerel schutzstaffel singlechannel steeringwheel terabecquerel ultraparallel