SEATTLE — The International Brotherhood of Teamsters, with its 1.4 million truck drivers, warehouse workers and other transportation laborers, does not represent any Amazon workers, nor is it organizing them. But the union keeps butting into the e-commerce giant, which ships billions of packages a year.

The Teamsters joined several other major labor unions in filing a petition Thursday asking the Federal Trade Commission to open a wide-ranging study into Amazon’s business practices. The unions, which represent more than five million American workers, hope to sic the antitrust regulator on a company increasingly reaching into the industries they represent.

“We wanted to demonstrate that there is a real desire to see them take this on,” said Michael Zucker, director of Change to Win, a federation of labor unions that led the effort.

The petition asks the F.T.C. to use its broad powers to gather nonpublic information about a company’s or industry’s effects on commerce. In a 28-page document with 149 footnotes, the unions lay out areas they think the F.T.C. should explore, including whether Amazon requires companies to use more of its services to succeed on its marketplace.