both parties to the third-party action will not need to refer to them. No assessment of the ultimate burden between PPG and Fluor can realistically be made without reference to the contracts.
Thus, on whatever legal basis any future damages stemming from plaintiffs’ claims are to be divided, the question of how to effectuate such a division seems to us to be one “arising out of or relating to this Agreement or the breach thereof.” Or at least the likelihood seems so substantial as to preclude meaningful third-party proceedings before arbitration takes place.
This is not to say that an arbitrator could not determine that certain aspects of PPG’s third-party complaint or the defenses raised thereto fall outside the scope of the arbitration clause. The arbitrator must ultimately pass on the outer boundaries of what is arbitrable. But we think that claims for contribution between PPG and Fluor, on whatever legal theory premised, are arbitrable at least until and unless it is otherwise decided by the arbitrator. The stay should have been granted.
PPG contends that cases holding that a tort claim may arise out of or relate to a contract are distinguishable because they do not involve third-party actions. This is a distinction without a difference. The district court was asked only to stay proceedings on the third-party action; the original litigation may continue as to liability to plaintiffs, and Fluor may assert defenses which it or PPG may have. See Rule 14, Fed.R.Civ.P.
Third-party plaintiffs also argue that it is against public policy to have the third-party complaint proceed independently through arbitration rather than in conjunction with the original action. But Puerto Rico like Congress encourages arbitration of disputes. 32 L.P.R.A. §§ 3201-29; see 9 U.S.C. §§ 1-9. If a claim of right to arbitration could be foreclosed whenever a dispute between the parties to the contract derives from another person’s claim against one of the parties, the utility of broad arbitration agreements would be undermined. Cf. Hilti, supra, 392 F.2d at 369. PPG’s contracts with Fluor Limited and Fluor Western provided for interpretation and performance of the contracts to be governed by California law, and we find nothing in Puerto Rico public policy that would prevent arbitration under California law. Cf. Hilti, supra, 392 F.2d at 373. Section 3 of the United States Arbitration Act calls for arbitration “in accordance with the terms of the agreement” and presents no obstacle to arbitration outside of Puerto Rico.
In a suit by different plaintiffs for damages from chlorine gas leakages from the PPG plant, Caraballo v. Pittsburgh Plate & Glass Co., Civ. No. c 373-431 (P.R.Super.Ct. Jan. 17, 1974), cert. denied (P.R.S.Ct. Feb. 26, 1974), reconsideration denied (March 15, 1974), the Superior Court of Puerto Rico granted a stay of proceedings on a similar third-party complaint pending arbitration under the same contracts and involving the same parties as in this case. Since we reach the same result as a matter of interpretation of the contracts under the United States Arbitration Act, we do not rely on principles of collateral estoppel.
Reversed and remanded for proceedings in accordance with this opinion.