Small Business Liability Protection Act - Amends the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 to provide (with exceptions) that persons shall be liable for response costs at a National Priorities List (NPL) facility as non-owners or operators only if the total of material containing a hazardous substance that the business arranged for disposal, transport, or treatment of, or accepted for transport, was greater than 110 gallons of liquid material or 200 pounds of solid material. Applies this exemption only to activities taking place before April 1, 2001.

Exempts a person from liability for response costs (with exceptions) at a NPL facility for municipal solid waste (MSW) as a non-owner or operator if the person is an owner, operator, or lessee of residential property from which all of the person's MSW was generated, or a certain small business or small charitable tax-exempt organization that generated all its MSW, with respect to the facility concerned.

Makes nongovernmental entities that commence a contribution action liable to the defendant for all reasonable costs of defending the action if the defendant is not liable based on the above-described exemptions.

Adds to the list of parties eligible for de minimis final settlements certain persons and businesses that demonstrate an inability or limited ability to pay response costs.

Revises conditions of eligibility for such settlements for de minimis parties.