Seeking records of Albion Malleable Iron Company

The Albion Malleable Iron Company, a vibrant locally-owned and controlled factory was in existence from 1888 until 1967.  In 1967 "the Malleable" merged with Hayes Industries and became known as Hayes-Albion.  With economic downturns, the company changed hands again and became Harvard Industries and closed it doors for good in 2002.  For 104 years this company had more of an impact of the city of Albion than just about any other entity.  The Albion Historical Society in Albion, MI is interested in locating the names and records of the earliest employees, but to date has been unsuccessful.  We are seeking advice from those who have done this kind of search before.  Where do historic company documents end up?