Liability of employer — contractors, subcontractors

1. Any person who has work done under contract on or about his premises which is an operation of the usual business which he there carries on shall be deemed an employer and shall be liable under this chapter to such contractor, his subcontractors, and their employees, when injured or killed on or about the premises of the employer while doing work which is in the usual course of his business. 2. The provisions of this section shall not apply to the owner of premises upon which improvements are being erected, demolished, altered or repaired by an independent contractor but such independent contractor shall be deemed to be the employer of the employees of his subcontractors and their subcontractors when employed on or about the premises where the principal contractor is doing work. 3. In all cases mentioned in the preceding subsections, the immediate contractor or subcontractor shall be liable as an employer of the employees of his subcontractors. All persons so liable may be made parties to the proceedings on the application of any party. The liability of the immediate employer shall be primary, and that of the others secondary in their order, and any compensation paid by those secondarily liable may be recovered from those primarily liable, with attorney's fees and expenses of the suit. Such recovery may be had on motion in the original proceedings. No such employer shall be liable as in this section provided, if the employee was insured by his immediate or any intermediate employer. 4. The provisions of this section shall not apply to the relationship between a for-hire motor carrier operating within a commercial zone as defined in section 390.020 or 390.041 or operating under a certificate issued by the Missouri department of transportation or by the United States Department of Transportation, or any of its subagencies, and an owner, as defined in section 301.010, and operator of a motor vehicle.