Can an employer agree with a union not to handle non-union-produce goods?

Yes, an employer can agree with a union to refrain from handling non-union-produced goods, often referred to as a "secondary boycott." This type of agreement may be part of collective bargaining negotiations to support unionized labor and discourage competition from non-union entities. However, such agreements must comply with labor laws, including the National Labor Relations Act in the U.S., which regulates union activities and employer practices. It's important for both parties to understand the legal implications and potential consequences of such agreements.