Employers and the health insurance industry are getting worried about a bill that would give workers denied benefits the right to sue in state courts. The Supreme Court has held that the Employee Retirement Income Security Act bars such state suits. But Senator Howard Metzenbaum (D-Ohio) and Representative Howard L. Berman (D-Calif.) have been picking up support for a measure reversing the high court's decision. Action in state courts would leave employers and insurers vulnerable to punitive damages, barred under ERISA, and force them to cope with a hodgepodge of state case law.