GREENWICH — The International Brotherhood of Teamsters union, a longtime critic of transportation-and-logistics giant XPO Logistics’ labor practices, is pushing for a new board chairman — but a shake-up does not appear imminent.

The Teamsters are seeking shareholders’ support, in the company’s May 15 board election, for a proposal to appoint an independent chairman who has not previously served as an XPO executive officer, arguing that such a leader would better respond to alleged labor violations and obstacles to the company’s growth. The union, however, has not suggested an individual to replace CEO and Chairman Bradley Jacobs in his latter position, and XPO said that he and the seven other board members are running uncontested for new one-year terms.

“With XPO at a critical juncture in its history, and facing significant industry headwinds, we believe independent leadership is needed more than ever,” Teamsters General Secretary-Treasurer Ken Hall wrote in a letter to shareholders.