Chelsea-based Metro Credit Union looks to make its second acquisition of the year by merging with Gloucester Fire Department Credit Union, one of the smallest credit unions in Massachusetts.

Metro has petitioned the Massachusetts Division of Banks to merge with Gloucester Fire Department Credit Union, which has about $694,000 in assets and 100 members.

With $2.4 billion in assets, Metro is the second largest credit union in Massachusetts behind Digital Federal Credit Union and the largest state-chartered credit union. It has about and 188,000 members, according to the National Credit Union Administration.

Metro in February merged with another Gloucester credit union, the Gloucester Municipal Credit Union, which had about 500 members and $2.3 million in assets. Metro expanded its membership at that time to include full-time, part-time and retired employees of the city of Gloucester, though Metro Credit Union’s membership already included people who live and work in Essex County.

Two other small Massachusetts credit unions are currently planning to merge into larger institutions. Credit Union of the Berkshires, a Pittsfield-based institution with about $22 million in assets and 1,900 members, plans to merge into Greylock Federal Credit Union, the largest credit union based in Western Massachusetts with about $1.4 billion in assets.

Worcester-based St. Vincent Hospital Credit Union, which has about $15 million in assets and 1,500 members, is planning to merge with Shrewsbury-based Central One Federal Credit Union, which has about $685 million in assets.