Contaminated property transactions include sales of real estate, leases, mergers, and acquisitions that involve a transfer of property that is impacted by historic pollution. Problems have been created in these transactions for parties on both sides by environmental laws that impose strict, joint and several and retroactive liability for environmental conditions on either the buyer or seller (lessor or lessee) who may have caused a release of contaminants. SEC environmental disclosure requirements have further complicated the situation by making it difficult for either party to agree to indemnify the other for such liabilities. Insurance policies have taken the place of indemnity agreements in these transactions and they can provide additional protection that addresses a wide range of environmental uncertainties. This article will consider a number of contaminated property transactions and review the use of insurance to facilitate their completion. It also provides briefcase studies that demonstrate the comprehensive nature of the protection that can be provided to neutralize environmental risks in these commercial transactions and to manage balance sheet liabilities even where the real estate is not sold.