Citing high costs and environmental regulations in California, a steel mill in Rancho Cucamonga is eliminating at least 100 jobs as it stops buying and processing scrap metal from outside sources. The change at Commercial Metals Co.’s Arrow Route factory also puts an end to its melting operation, which was one of the few remaining plants in California where law enforcement disposed of seized firearms. The facility will remain open and continue producing rebar for the construction industry made from steel shipped from other factories. But they will no longer buy and melt scrap metal, including guns confiscated from felons by police departments. One employee who received a layoff notice, speaking on a condition of anonymity because he feared retribution, said law enforcement agencies from as far away as Fresno dropped off guns on a regular basis, as did the police and sheriff’s departments from Los Angeles. Bill Russell, a spokesman from the Ontario Police Department, said they were looking for other ways to dispose of the weapons. “We know that there’s a place in Arizona that melts firearms, but that’s just not feasible for us,” Russell said. “We’re looking at alternatives.” Jodi...