As if tetraethyl lead in gasoline wasn't bad enough, they also added ethylene dichloride and/or ethylene dibromide, which acted as a lead scavengers, preventing deposits of insoluble lead (II) oxide from forming and clogging up engines/exhaust equipment. Instead, water-soluble-at-high-temperatures lead (II) chloride and lead (II) chloride were blasted out the tailpipes of vehicles using tetraethyl lead. These are mildly soluble at ambient temperatures, allowing the lead to permeate even further than it otherwise would have.