The Association was founded in 1969 to fill a need by the shipping industry to have effective labor relations management of employees loading and unloading ships in Eastern Canada. The random arrival and departure of ships necessitates longshoremen working for many employers throughout the year and because of this, the industry required that a common association be established to act on its behalf in dealing with these employees.

The Association is appointed as agent to its member companies pursuant to Section 34 of the Canada Labour Code. Section 34 deals with the longshoring industry and allows for employees of two or more employers to have jurisdiction over longshoring work within a geographic area. Section 34 (3) of the Code dictates that one agent be appointed by the employers to act on their behalf and to discharge the duties and responsibilities of an employer.