Superfund Equitable Liability and Improved Cleanup Act

Superfund Equitable Liability and Improved Cleanup Act - Amends the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 to revise liability provisions to make the following persons liable for costs and damages under such Act: (1) owners or operators of a site or facility if such persons should have known that disposal was likely to result in the release of a hazardous substance that would endanger public health or welfare or the environment; and (2) any person if the person violated any applicable environmental statute, plan, or order in effect at the time of disposal and the violation contributed to such endangerment or the person's action contributed to such endangerment and the person should have known that the disposal would cause such endangerment or would result in liability under common law.

Directs the Administrator of the Environmental Protection Agency to promulgate regulations establishing numerical standards for each hazardous substance, pollutant, and contaminant. Applies such standards to remedial actions at each site on the National Priorities List unless the Administrator: (1) determines that the standards are not sufficiently protective of human health or the environment; or (2) grants a waiver of the standards at the site in response to a petition from a party responsible for cleanup at the site.

Requires the Administrator to promulgate regulations establishing deadlines for any person who is liable with respect to a site for the completion of remedial action investigation, design, and implementation. Prescribes civil penalties for violations of deadlines.

Prohibits the President from selecting the capping of a site as a remedial action unless the President determines that compliance with the numerical cleanup standards is not technologically feasible.

Amends the Internal Revenue Code to modify the amount of excess minimum taxable income upon which environmental tax is imposed (thereby making an increased amount of corporate income subject to the tax).