OKLAHOMA CITY - A hydraulic fracturing company on Oct. 9 filed a brief in an Oklahoma federal court arguing that the company that made a lithium battery pack that exploded on a fracking rig and injured a worker has a direct duty under Oklahoma law to indemnify the fracking operator because the explosion was caused by an allegedly defective design (Jacob McGehee, et al. v. Southwest Electronic Energy Corporation, et al. and Southwest Electronic Energy Corporation v. Engineered Power LP, et al., No. 15-145, W.D. Okla.).