sentences:  CHA employs approximately 3,500 staff members in Cambridge, Everett, Malden, Medford, Revere, and Somerville, Massachusetts.65% of CHA's staff are unionized.As of 2013, more than 40% of CHA staff (1,600+) live within the area of Cambridge, Chelsea, Everett, Malden, Medford, Revere, Somerville, and Winthrop.