A safety pledge this week could mean more training for some workers at Iowa packing plants. Companies that employ people to clean packing plants in Nebraska and Iowa signed an agreement today with OSHA to make the job safer. A man died this week at a Des Moines beef processing plant when he fell into a machine that apparently was running as he was cleaning it. The Omaha area office of the Occupational Health and Safety Administration welcomed the offer by contractors to do training sessions and on-site inspections the agency doesn’t have the money or staff to provide. Industry analysts say contractors employ thousands of immigrant laborers, many with no health coverage and few safety protections, to do the dangerous job of daily cleaning at slaughterhouses.