(820 ILCS 305/1) (from Ch. 48, par. 138.1)
    Sec. 1. This Act may be cited as the Workers' Compensation Act.
    (a) The term "employer" as used in this Act means:
    1. The State and each county, city, town, township, incorporated village, school district, body politic, or municipal corporation therein.
    2. Every person, firm, public or private corporation, including hospitals, public service, eleemosynary, religious or charitable corporations or associations who has any person in service or under any contract for hire, express or implied, oral or written, and who is engaged in any of the enterprises or businesses enumerated in Section 3 of this Act, or who at or prior to the time of the accident to the employee for which compensation under this Act may be claimed, has in the manner provided in this Act elected to become subject to the provisions of this Act, and who has not, prior to such accident, effected a withdrawal of such election in the manner provided in this Act.
    3. Any one engaging in any business or enterprise referred to in subsections 1 and 2 of Section 3 of this Act who undertakes to do any work enumerated therein, is liable to pay compensation to his own immediate employees in accordance with the provisions of this Act, and in addition thereto if he directly or indirectly engages any contractor whether principal or sub-contractor to do any such work, he is liable to pay compensation to the employees of any such contractor or sub-contractor unless such contractor or sub-contractor has insured, in any company or association authorized under the laws of this State to insure the liability to pay compensation under this Act, or guaranteed his liability to pay such compensation. With respect to any time limitation on the filing of claims provided by this Act, the timely filing of a claim against a contractor or subcontractor, as the case may be, shall be deemed to be a timely filing with respect to all persons upon whom liability is imposed by this paragraph.
    In the event any such person pays compensation under this subsection he may recover the amount thereof from the contractor or sub-contractor, if any, and in the event the contractor pays compensation under this subsection he may recover the amount thereof from the sub-contractor, if any.
    This subsection does not apply in any case where the accident occurs elsewhere than on, in or about the immediate premises on which the principal has contracted that the work be done.
    4. Where an employer operating under and subject to the provisions of this Act loans an employee to another such employer and such loaned employee sustains a compensable accidental injury in the employment of such borrowing employer and where such borrowing employer does not provide or pay the benefits or payments due such injured employee, such loaning employer is liable to provide or pay all benefits or payments due such employee under this Act and as to such employee the liability of such loaning and borrowing employers is joint and several, provided that such loaning employer is in the absence of agreement to the contrary entitled to receive from such borrowing employer full reimbursement for all sums paid or incurred pursuant to this paragraph together with reasonable attorneys' fees and expenses in any hearings before the Illinois Workers' Compensation Commission or in any action to secure such reimbursement. Where any benefit is provided or paid by such loaning employer the employee has the duty of rendering reasonable cooperation in any hearings, trials or proceedings in the case, including such proceedings for reimbursement.
    Where an employee files an Application for Adjustment of Claim with the Illinois Workers' Compensation Commission alleging that his claim is covered by the provisions of the preceding paragraph, and joining both the alleged loaning and borrowing employers, they and each of them, upon written demand by the employee and within 7 days after receipt of such demand, shall have the duty of filing with the Illinois Workers' Compensation Commission a written admission or denial of the allegation that the claim is covered by the provisions of the preceding paragraph and in default of such filing or if any such denial be ultimately determined not to have been bona fide then the provisions of Paragraph K of Section 19 of this Act shall apply.
    An employer whose business or enterprise or a substantial part thereof consists of hiring, procuring or furnishing employees to or for other employers operating under and subject to the provisions of this Act for the performance of the work of such other employers and who pays such employees their salary or wages notwithstanding that they are doing the work of such other employers shall be deemed a loaning employer within the meaning and provisions of this Section.
    (b) The term "employee" as used in this Act means:
    1. Every person in the service of the State, including members of the General Assembly, members of the Commerce Commission, members of the Illinois Workers' Compensation Commission, and all persons in the service of the University of Illinois, county, including deputy sheriffs and assistant state's attorneys, city, town, township, incorporated village or school district, body politic, or municipal corporation therein, whether by election, under appointment or contract of hire, express or implied, oral or written, including all members of the Illinois National Guard while on active duty in the service of the State, and all probation personnel of the Juvenile Court appointed pursuant to Article VI of the Juvenile Court Act of 1987, and including any official of the State, any county, city, town, township, incorporated village, school district, body politic or municipal corporation therein except any duly appointed member of a police department in any city whose population exceeds 500,000 according to the last Federal or State census, and except any member of a fire insurance patrol maintained by a board of underwriters in this State. A duly appointed member of a fire department in any city, the population of which exceeds 500,000 according to the last federal or State census, is an employee under this Act only with respect to claims brought under paragraph (c) of Section 8.
    One employed by a contractor who has contracted with the State, or a county, city, town, township, incorporated village, school district, body politic or municipal corporation therein, through its representatives, is not considered as an employee of the State, county, city, town, township, incorporated village, school district, body politic or municipal corporation which made the contract.
    2. Every person in the service of another under any contract of hire, express or implied, oral or written, including persons whose employment is outside of the State of Illinois where the contract of hire is made within the State of Illinois, persons whose employment results in fatal or non-fatal injuries within the State of Illinois where the contract of hire is made outside of the State of Illinois, and persons whose employment is principally localized within the State of Illinois, regardless of the place of the accident or the place where the contract of hire was made, and including noncitizens, and minors who, for the purpose of this Act are considered the same and have the same power to contract, receive payments and give quittances therefor, as adult employees.
    3. Every sole proprietor and every partner of a business may elect to be covered by this Act.
    An employee or his dependents under this Act who shall have a cause of action by reason of any injury, disablement or death arising out of and in the course of his employment may elect to pursue his remedy in the State where injured or disabled, or in the State where the contract of hire is made, or in the State where the employment is principally localized.
    However, any employer may elect to provide and pay compensation to any employee other than those engaged in the usual course of the trade, business, profession or occupation of the employer by complying with Sections 2 and 4 of this Act. Employees are not included within the provisions of this Act when excluded by the laws of the United States relating to liability of employers to their employees for personal injuries where such laws are held to be exclusive.
    The term "employee" does not include persons performing services as real estate broker, broker-salesman, or salesman when such persons are paid by commission only.
    (c) "Commission" means the Industrial Commission created by Section 5 of "The Civil Administrative Code of Illinois", approved March 7, 1917, as amended, or the Illinois Workers' Compensation Commission created by Section 13 of this Act.
    (d) To obtain compensation under this Act, an employee bears the burden of showing, by a preponderance of the evidence, that he or she has sustained accidental injuries arising out of and in the course of the employment.
(Source: P.A. 102-1030, eff. 5-27-22.)