Nothing in this subchapter shall be construed to affect either the tort law or the law governing the interpretation of insurance contracts of any State. The definitions of pollution liability and pollution liability insurance under any State law shall not be applied for the purposes of this subchapter, including recognition or qualification of risk retention groups or purchasing groups.

The authority to offer or to provide insurance under this subchapter shall be limited to coverage of pollution liability risks and this subchapter does not authorize a risk retention group or purchasing group to provide coverage of any other line of insurance.