A New York firm that is developing the World Trade Center site has joined a local developer who has proposed building an 8,000-seat arena to house the Pirates in Portland or Westbrook.

David Emil, president of Lower Manhattan Development Corp., has joined Westbrook developer Jason Snyder in developing two properties he owns near the Maine Turnpike. Emil is the son of Arthur Emil, Snyder’s business partner who died on July 6. He was 85.

Snyder proposed building an 8,000-seat entertainment and sports arena to house the Pirates near the turnpike in Portland or Westbrook. The proposal calls for a 150,000-square-foot arena on a 63-acre site in Portland or on a 60-acre site in Westbrook between exits 46 and 47 of the turnpike.

Snyder proposed building the arena in conjunction with his proposed Stroudwater Place, a $300 million retail and commercial center in Westbrook. He also wants to renovate the Cumberland County Civic Center into a dedicated convention center. Snyder said David Emil has agreed to oversee the three projects.

“The project continues to stay on track,” Snyder said.