225 ILCS 470/15

To enforce this Act and other Acts dealing with weights and measures and enforceable by him, the Director is vested with special police powers, and may without formal warrant both arrest any violator of such Acts and seize for use as evidence incorrect or unsealed weights and measures or amounts or packages of commodity found to be used, retained, offered or exposed for sale or sold in violation of law. In performance of his official duties, the Director may enter and go into or upon any structure or premises without formal warrant and may stop any person and require him to proceed, with or without any vehicle of which he may be in control, to a place specified by the Director.