415 ILCS 70/2
Any contractor or subcontractor who, in the performance of a construction or excavation contract, discovers any substance or material, the existence of which has not previously been disclosed to the contractor by the owner, and applicable law, rule or regulation either (i) requires the removal or containment thereof, or (ii) prohibits that person from proceeding unless he is duly licensed therefore and he is not so licensed; and either (i) the removal or containment thereof cannot be effectuated without a cessation of the work; or (ii) applicable law, rule or regulation requires him to cease work; or, (iii) when the continuation of work exposes any person to a substantial risk; and (iv) if such contract contains no provision allocating responsibility or liability in the event of an undisclosed discovery of such substance or material, the contractor, or subcontractor and any other party whose work is impaired, impeded or prohibited as a result thereof may interrupt performance of the contract without penalty until the substance or material is removed or contained by the owner of the land or improvement and be awarded any damages caused by the delay. The owner shall have the right to terminate the contract upon payment to the contractor of the amount of any services or materials supplied or expended plus any damages for the delay to the date of termination of the contract.
415 ILCS 70/2