The district court issued an injunction under section 10® of the National Labor Relations Act, 29 U.S.C. § 160®, ordering respondent Irving Ready-Mix, Inc. to stop certain unfair labor practices pending a final administrative decision by the National Labor Relations Board. Irving Ready-Mix has appealed, but we find no error or *568 abuse of discretion by the district judge. We affirm.
I. Factual and Procedural Background
Respondent Irving Ready-Mix, Inc. sells, delivers, and installs ready-mix concrete from its five plants in northern Indiana. For many years, the ready-mix concrete truck drivers employed by Irving Ready-Mix have been represented by the Chauffeurs, Teamsters & Helpers, Local Union No. 414, a local of the International Brotherhood of Teamsters. A collective bargaining agreement was in effect from June 1, 2005 through May 31, 2010.
As the agreement’s expiration date neared, the union and management met to negotiate a new agreement. The employer insisted that a new agreement would have to allow it to reduce its total labor costs (wages plus benefits) from approximately $43.00 per hour to about $31.00 per hour. The union refused, management stuck to its position, and the old agreement expired on May 31, 2010 without a replacement. The drivers went on strike on June 1st.
The employer then took the actions at the center of this lawsuit. It announced that it no longer recognized the Union as the drivers’ collective bargaining representative. Instead, it contacted the drivers directly, offering to employ them individually on new terms consistent with management’s last offer. A few drivers resigned from the union and returned to work, including one member of the union’s bargaining committee. The strike ended on July 19, 2010, and more drivers returned to work at the lower wage rates and on terms less favorable than those of the old collective bargaining agreement.
The union filed charges of unfair labor practices with the National Labor Relations Board. The charges relevant to this appeal all stem from the employer’s refusal to recognize the union after the old collective bargaining agreement expired, despite the absence of evidence that the union had lost support of a majority of the drivers. An administrative law judge heard evidence from the parties on September 29 and 30, 2010. The next week, on October 5, 2010, NLRB regional Director Rik Lineback filed this petition in the district court seeking a section 10(j) injunction pending a final decision by the Board.
Before the district court ruled on the injunction request, the ALJ issued a decision finding that all but one of the unfair labor practice charges had merit. First, the ALJ determined that the employer was subject to the unfair labor practices restrictions of the National Labor Relations Act (NLRA) as a result of the type of collective bargaining agreement it held with the union. Second, the ALJ concluded that the employer violated two of those restrictive provisions. We elaborate briefly on the ALJ’s conclusions.
In the first step of his analysis, the ALJ found that the employer’s collective bargaining agreement with its employees was made pursuant to section 9(a) of the NLRA, 29 U.S.C. § 159(a). Under this section, a union chosen for purposes of collective bargaining by the majority of employees in a unit is considered the exclusive representative for negotiating conditions of employment. Other provisions of the Act prohibit practices that interfere with this section 9(a) relationship. The relevant provision here is section 8(a), which prohibits unfair practices by the employer. See NLRA § 8(a)-(b), (d); 29 U.S.C. § 158(a)-(b), (d).
To avoid this result, the employer argued that its relationship with the union was governed not by section 9(a) but by section 8(f), under which it would have been excepted from the restrictions of section 8(a). Section 8(f) of the NLRA al *569 lows an employer “engaged primarily in the building and construction industry” to enter into a collective bargaining agreement with a union before the union has established majority status. 1 See 29 U.S.C. § 158(f). As a result of this special situation, section 8(f) agreements are not subject to the full set of unfair labor practices restrictions like traditional section 9(a) agreements. Under section 8(f), the employer’s unilateral termination of recognition after expiration of the collective bargaining agreement would have been permitted. The ALJ rejected the employer’s argument, relying on Board precedents that ready-mix concrete employers are not “engaged primarily in the building and construction industry” within the meaning of section 8(f).
The ALJ also noted that the employer’s agreement with the union exhibited “no evidence” that it was a section 8(f) agreement. The employer and the union had entered into at least four consecutive five-year contracts. Those contracts allowed new employees thirty days to join the union, rather than the seven days permitted in contracts under section 8(f). Further, the drivers’ employment with the employer was stable and long-term, not the sporadic and site-specific work that characterizes many construction jobs for which section 8(f) was designed. Concluding that section 9(a) controlled the parties’ relationship, the ALJ then found that the employer violated subsections 8(a)(1) and 8(a)(5) by communicating directly with the drivers during the strike and unilaterally changing the terms of the drivers’ employment.
A few weeks later, on January 28, 2011, the district court granted the Director’s motion for a preliminary injunction pending a final decision by the Board. The court ordered the employer to recognize the union as the drivers’ exclusive collective bargaining representative; to restore wages, benefits, and working conditions to what they had been under the old collective bargaining agreement; and, to stop dealing directly with individual employees regarding wages and other terms of employment. The employer then filed this appeal.
II. Analysis
We discuss first the applicable law governing the injunction and then turn to the specific factual and legal issues concerning the employer’s attempt to take advantage of section 8(f) to withdraw recognition from the union.
A. Section 100) of the National Labor Relations Act
Under section 10(j), a district court may order injunctive relief pending the Board’s final disposition of an unfair labor practice claim if such relief would be “just and proper.” 29 U.S.C. § 160(j);
Line-back v. Spurlino Materials, LLC,
An injunction granted under section 10(j) is an “extraordinary remedy” and should be granted only in those situations in which effective enforcement of the Act is threatened by delay in the Board’s dispute resolution process. See
Bloedorn v. Francisco Foods, Inc.,
Here, the district court determined that the Director presented sufficient evidence for each of the four elements such that a section 10(j) injunction was warranted. Finding the employer’s practices to be “enormously destructive” to the union’s organizational efforts, the court had no trouble concluding that the union had established irreparable harm. This conclusion was clearly correct. We have previously found circumstances such as these — a decline in the union’s membership, loss of employee benefits, and ongoing erosion of the employer-union relationship — to be sufficient to establish irreparable harm. See
Spurlino Materials,
B. Classifying the Ready-Mix Concrete Business
The nature of the employer’s obligations following the expiration of the collective bargaining agreement depends
*571
on whether the agreement was constituted according to NLRA section 9(a) or section 8(f). If Irving Ready-Mix as a ready-mix concrete company qualifies under section 8(f) as “an employer engaged primarily in the building and construction industry,” then it is not subject to some of the NLRA’s unfair labor practice restrictions in section 8(a) and was entitled to withdraw recognition from the union. See
Engineered Steel Concepts, Inc.,
Ready-mix concrete, involving the delivery of fresh wet concrete manufactured at a plant to a work site in a transit mixer truck, is not a recent innovation. 2 This court and the Board have had occasion to address the activities of ready-mix concrete companies in several cases. The Board has previously decided this very question under section 8(f) and concluded that a ready-mix concrete company is not an “employer engaged primarily in the building and construction industry.” Irving Ready-Mix does not contend that it presents a novel claim here. Rather, it suggests that the Board precedents on which the ALJ and the district court based their decisions were wrongly decided.
The ALJ and district court relied on
J.P. Sturrus Corp.,
Since
J.P. Sturrus,
the Board has repeatedly held that ready-mix concrete delivery companies and similar businesses that deliver construction materials to job sites are not engaged in construction for purposes of section 8(f). See
Engineered
*572
Steel Concepts,
Like other construction material manufacturers and suppliers, ready-mix concrete falls in a grey area between construction labor, such as carpentry for framing homes, and manufacture of building materials, such as bricks or nails. But section 8(f) requires that a line be drawn somewhere and drawing that line is more the Board’s job than it is ours. As a general matter, we defer to the Board’s judgment with respect to such specialized issues of labor law. See
Local 15, IBEW v. NLRB,
The employer here nevertheless insists that
J.P. Sturrus
was wrongly decided and that we should treat it as an aberration. To support this contention, the employer relies on the Board’s earlier decision in
Carpet, Linoleum and Soft Tile Local Union No. 1247 (Indio Paint & Rug Center),
Through its detailed analysis, the Indio Paint decision gave ALJs guidance regarding the scope of the term “building and construction industry.” That industry includes employers engaged in “the provision of labor whereby materials and constituent parts may be combined on the building site,” but not those carrying out the manufacture and assembly of products installed by others at the construction site. Id. at 959. In this case, the employer’s principal argument is that, under the methodology of Indio Paint, ready-mix concrete companies are “building and construction” companies. The employer contends that the Board’s decision in J.P. Sturms, which did not cite Indio Paint, was flawed because it broke from the Indio Paint precedent without explanation or justification.
In our view, the employer’s argument is undermined by the Board’s favorable treatment of J.P. Sturrus in cases involving ready-mix concrete companies over the past twenty years. If later cases had adopted contradictory positions or questioned the discrepancy, the employer’s argument might carry more weight. But its *573 argument that J.P. Sturrus failed to properly apply section 8(f) runs head-on into the several cases consistently upholding and applying that decision.
Contrary to the employer’s contention, this pattern of Board precedent is not like the deviation we described in
Milwaukee and Southeast Wisconsin District Council of Carpenters v. Rowley-Schlimgen, Inc.,
There was no such aberration here. The solid line of cases reiterating J.P. Sturms’ holding supports the district court’s conclusion that the Director is likely to succeed on the merits.
We conclude that the district court did not err. We Affirm its order.
Notes
. Section 8(f) was enacted to accommodate the special needs of the building and construction industry. See H.R.Rep. No. 741, at 19-20 (1959). In
Operating Engineers Pension Trust v. Beck Engineering & Surveying Co.,
Congress recognized that the representation procedures prescribed in Section 9 of the Act were largely unsuited to the peculiar circumstances of the construction industry, where employers ordinarily hire on a project-by-project basis ... [and] where an employer who might employ no one unless he is working on a project, must nevertheless know his anticipated labor costs before making a bid and must have access to a readily available pool of skilled craftsmen.
. See F. Biasioli, "Ready Mix Concrete: An Old-New Material for the 21st Century" in Creating with Concrete, eds. Ravindra K. Dhir, Peter C. Hewlett, and M. Roderick Jones (Thomas Telford Publishing 1999), 170 (discussing the scientific development of ready-mix concrete in the early 1900s).
. Section 8(e) provides another exception to the NLRA's unfair labor practices provisions for agreements between labor organizations and an employer "in the construction industry” relating to the "contracting or subcontracting of work to be done at the site of construction.” 29 U.S.C. § 158(e); see also
Inland Concrete Enterprises, Inc.,
