In Port Elevator-Brownsville, L.L.C. v. Casados, 358 S.W.3d 238 (Tex. 2012), the Texas Supreme Court observed it had "long held that the Labor Code and the rule against split work forces require employers to elect workers' compensation coverage for all employees." 358 S.W.3d at 239. Casados worked for Staff Force, a temporary staffing agency, which provided Casados to perform general labor for Port Elevator. Id. at 240. Casados suffered a fatal, work-related injury. Id. Staff Force and Port Elevator both carried workers' compensation insurance. Id. Port Elevator's carrier, Texas Mutual, claimed that Casados was a Staff Force employee and not a Port Elevator employee and denied workers' compensation coverage. Id. Port Elevator raised the affirmative defense that workers' compensation was the plaintiffs' exclusive remedy. Id. The plaintiffs, in response to Port Elevator's motion for summary judgment, argued that the policy did not cover Casados because Port Elevator did not pay premiums for temporary employees. Id. The Texas Supreme Court reaffirmed its holding that "the employer may not split its work force by electing coverage for some employees, but not coverage for all." Id. at 241. The court rejected the plaintiffs' argument that Port Elevator intended to and did exclude Casados from coverage because Port Elevator did not pay premiums for temporary workers. Id. at 243. The court explained that premiums are an issue between the employer and the insurer; they do not affect the employee's coverage. Id. Therefore, even if Port Elevator's policy had set out certain premiums solely for temporary workers and it had not paid those premiums, Casados would still have been covered under the policy, and the failure to pay premiums would be an issue between Port Elevator and Texas Mutual. Id. at 244. Moreover, a clear and unambiguous attempt to exclude Casados from coverage would violate the rule against splitting work forces. Id.