Richard Hellmann, creator of Hellmann's mayonnaise, had his first big factory at 495 / 497 Steinway Street from 1915 to 1922.  In 1922, operations moved to a larger factory at 34-08 Northern Boulevard.
^Richard Hellmann, Inc. Convention Tomorrow." A convention, banquet and dance has been arranged by Richard Hellmann, Inc, of 497 Steinway Avenue, Long Island City, for tomorrow, for members of the organization, its out of town representatives and its business friends. The program for the day includes a trip through the factory, followed by a convention at 4 o'clock at the Hotel McAlpin for distributors of the firm's products." -- Brooklyn, NY: Daily Star. Friday, 25 February 1921. Page 2.
^Smith, Andrew F. Hellmann's Mayonnaise: A History.