Federal labor board nominee John Ring will likely have to sit out cases involving some big technology and finance companies, and possibly a dispute over the ongoing attempt to organize aerospace workers at Boeing plants.

Ring’s former firm, Morgan Lewis, represents Amazon, Microsoft, J.P. Morgan Chase & Co., Pfizer, and other large corporations in cases currently before the National Labor Relations Board, according to a document obtained by Bloomberg Law. Morgan Lewis also represents Boeing in three disputes in which formal proceedings have not been instituted before the board.

The nominee will likely have to recuse himself from the cases current cases before the board—and potentially others involving the companies—for two years to avoid some of the ethical issues that have plagued another recently-confirmed member, William Emanuel (R). The board recently voided a closely-watched decision after the agency’s inspector general found that Emanuel shouldn’t have participated in the case.

“I take this issue very seriously,” Ring said at a nomination hearing last week, where he pledged to provide the client list before a Senate committee votes on his nomination. “I don’t want to put another cloud over the NLRB.”

Morgan Lewis also represents management in union petitions to organize workers at the General Electric Company, Aramark, DaVita, Google, and Dell, among other large corporations.

The firm is not currently involved in the latest effort to organize Boeing workers in South Carolina. It’s not immediately clear whether Ring would be permitted to participate in any case that comes before the board related to that organizing drive.

The International Association of Machinists have said the Boeing organizing moves are part of a broad attempt to organize aerospace workers in the Southern half of the country.

Ring has not necessarily been involved in all of the cases listed. He has done work for several public union pensions and retirement funds, and Grosvenor Capital Management, a large private equity firm. The nominee disclosed that work although it wasn’t required.