Protests Relating to Federal Supply Schedule Orders
Yes, the other BPA holders could file a protest at the order level. A FAR part 8 BPA is established under a Federal Supply Schedule contract (see FAR 8.405-3(a)(1)). Both the Government Accountability Office (GAO) and the U.S. Court of Federal Claims (COFC) have taken jurisdiction over protests relating to the issuance of orders under Federal Supply Schedules (see Severn Cos., Inc., B-275717, 97-1 CPD ¶ 181 and IDEA International, Inc. v. United States, Nos. 06-652C, 06-717C (Fed. Cl. Dec. 1, 2006)). Thus, a BPA holder could file a protest with the agency, the GAO, or the COFC. Each is discussed separately below.

Protests to the Agency (FAR 33.103)
The FAR doesn't place limitations on what types of protests an agency may sustain. However, an agency may dismiss a protest if it is untimely or if the protestor cannot establish that it is an "interested party for the purpose of filing a protest". This term is defined at FAR 33.101 as:

"an actual or prospective offeror whose direct economic interest would be affected by the award of a contract or by the failure to award a contract."

Protests to the GAO (4 CFR Part 21)
Similarly, the GAO will dismiss a protest if it is untimely or if the protestor cannot establish that it is an "interested party" as defined at 4 CFR 21.0(a). Additionally, the GAO will dismiss protests based on any of the following:
·  Contract administration
·  SBA issues
·  Affirmative determination of responsibility by the contracting officer
·  Procurement integrity
·  Groundless protests
·  Procurements by agencies that are not "Federal Agencies" as defined at 40 U.S.C. 472
·  Subcontract protests
·  Suspension and debarment
·  Competitive range
·  Decision of agency tender official to file/not file a protest
[4 CFR 21.5]

For protests that clear these hurdles, the GAO will review an agency action to determine if it complies with statute or regulation. (31 U.S.C. 3554(b)(1)). Under this standard, a protester must establish that the contracting agency violated a statute or regulation or has taken a discretionary action without a rational basis. The protester must also demonstrate that it would have had a substantial chance at award had the agency not erred. (See Armorworks Enters., LLC, Comp. Gen. Dec. B-400394.3, 2009 CPD ¶ 79). If a protester can prove these claims, it's likely that the GAO would sustain the protest.

Protests to the COFC
A protester must also establish that it is an "interested party" when filing a protest at the COFC. See Distributed Solutions, Inc. v. United States, 539 F.3d 1340 (Fed. Cir. 2008). The COFC doesn't have prescribed timeliness rules, but will dismiss protests based on alleged improprieties in the solicitation if they were filed after the solicitation closing date. See Blue & Gold Fleet, L. P. v. United States, 492 F.3d 1308 (Fed. Cir. 2007). The COFC will likely sustain a protest if they find that the agency action is arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law, Banknote Corp. of Am. v. United States, 365 F.3d 1345 (Fed. Cir. 2004).

"Fair Share" of Work to BPA Holders
For orders below the micro-purchase threshold, both FAR 8.405-1(b) and 8.405-2(c)(1) state that the ordering activity should attempt to distribute orders among contractors. The FAR does not prescribe a method for doing this, but this could be done on a rotational basis or by selecting at random from the BPA holders. Note that orders above the micro-purchase threshold require a competitive solicitation and/or determination of best value to select contractors--there is no "fair share" consideration (see FAR 8.405-1 and -2). Competition may or may not result in an equitable distribution of orders.