ATLANTA—Federal workplace safety officials are proposing nearly $1 million in fines against four companies following a January liquid nitrogen leak that killed six workers at a northeast Georgia poultry processing plant. U.S. Labor Secretary Marty Walsh announced the citations and fines by the U.S. Occupational Safety and Health Administration on Friday. Foundation Food Group, which owns the Gainesville plant, was cited for 26 violations with a proposed fine of $595,474. Packers Sanitation Services Ltd., which provided cleaning services at the plant, was cited for 19 violations with a proposed fine of $286,720. Messer LLC, which delivered the nitrogen, was cited for six violations and faces a proposed fine of $74,118. FS Group Inc, which manufactures and services equipment, was cited for eight violations with a proposed fine of $42,325. OSHA fines and citations are often lowered following informal and formal appeal processes. Foundation Food did not immediately reply to an …