Appellants also argue that a person under a duty to the public has a non-delegable duty to see that work is carefully performed to avoid injury to others. See Lamb v. S. Unit Jehovah's Witnesses, 232 Minn. 259, 263, 45 N.W.2d 403, 406 (1950) (addressing duty to public, when church engaged independent contractor to connect church building to sewer main, trench on boulevard was filled in negligently, and pedestrian on boulevard was injured). In such a case, when injurious consequences must be expected to arise, an owner cannot relieve itself of liability by employing another.

Blackhawk here seeks to avoid liability primarily on the theory that under its contract with Haughton it was Haughton's obligation to maintain the elevator in safe condition, and that if the accident was caused by the failure of any of the safety devices to function properly such a result was brought about by Haughton's negligence. The trial court instructed the jury that Blackhawk had a non-delegable duty to use reasonable care to furnish safe elevator transportation. Such instruction appears to properly state the applicable law of Minnesota. Lamb v. South Unit Jehovah's Witnesses, 232 Minn. 259, 45 N.W.2d 403, 33 A.L.R.2d 1; Pacific Fire Ins. Co. v. Kenny Boiler Mfg. Co., 201 Minn. 500, 277 N.W. 226. In the Lamb case, 45 N.W.2d at page 406 the court says:

It is the general rule in Minnesota that an employer is not liable for the acts of an independent contractor or its servants albeit there are many exceptions to this rule. Lamb v. South Unit Jehovah's Witnesses, 1950, 232 Minn. 259, 45 N.W.2d 403, 406, 33 A.L.R.2d 1. The main test is the degree of control the employer has over the time, place and manner of performing the work of the independent contractor. See Mix v. City of Minneapolis, 1945, 219 Minn. 389, 18 N.W.2d 130, 136.

In granting summary judgment, the district court concluded that Brake and Mersey were independent contractors, and that Airport Taxi could not, therefore, be vicariously liable for Mersey's actions. Specifically the district court held that Mersey was an independent contractor of Brake, and Brake was an independent contractor of Airport Taxi. As a general rule, an employer is not liable for the acts of independent contractors. Lamb v. South Unit Jehovah's Witnesses, 232 Minn. 259, 263, 45 N.W.2d 403, 406 (1950). The determination of an employment relationship is a mixed question of fact and law. Lakeland Tool Eng'g, Inc. v. Engle, 450 N.W.2d 349, 352 (Minn.App. 1990).

Generally, an employer is not liable for the acts or omissions of an independent contractor or its agents. Lamb v. South Unit Jehovah's Witnesses, 232 Minn. 259, 263, 45 N.W.2d 403, 406 (1950); Restatement (Second) of Torts § 409 (1965). The general rule, however, is riddled with exceptions.

Under Minnesota law, an employer may be responsible for conduct of an independent contractor. Lamb v. South Unit Jehovah's Witnesses, 232 Minn. 259, 263, 45 N.W.2d 403, 406 (1950) (noting that the general rule of nonliability for the conduct of independent contractors is merely "a preamble to the catalog of its exceptions") (quoting Pacific Fire Ins. Co. v. Kenny Boiler Mfg. Co., 201 Minn. 500, 503, 277 N.W. 226, 228 (1937)). Kern, while deciding the status of foster parents, did not determine an employer's vicarious liability for an independent contractors' torts. Kern, 322 N.W.2d at 189 (concluding that county's insurance policy covering "employees" did not extend to foster parents).

Larson v. Le Mere, 1945, 220 Minn. 25, 32, 18 N.W.2d 696, 700; Willner v. Wallinder Sash Door Co., 1947, 224 Minn. 361, 369, 28 N.W.2d 682, 686; Fahey v. Terp, 1952, 235 Minn. 432, 433, 51 N.W.2d 273, 274; and (f) that as a general rule one is not liable for the acts of an independent contractor although "it would be proper to say that the rule is now primarily important as a preamble to the catalog of its exceptions". Pacific Fire Ins. Co. v. Kenny Boiler Mfg. Co., 1937, 201 Minn. 500, 503, 277 N.W. 226, 228; Lamb v. South Unit Jehovah's Witnesses, 1950, 232 Minn. 259, 263, 45 N.W.2d 403, 406, 33 A.L.R.2d 1. It has been said, too, that the burden is upon the plaintiff to show that his case comes within an exception to the rule of non-liability. Union Tank Supply Co. v. Kelley, 5 Cir., 1948, 167 F.2d 811, 815, cert. den. 335 U.S. 827, 69 S.Ct. 54, 93 L.Ed. 381; Terry v. A.P. Green Fire Brick Co., E.D.Ark., 1958, 164 F. Supp. 184, 188, appeal dismissed, 8 Cir., 268 F.2d 213. The plaintiff has no quarrel with these propositions of Minnesota law. He argues that, accepting these principles, the United States is liable for his injuries because the government at all times retained active control of the safety program at the Arsenal, and that, in any event, it cannot escape its liability here by hiring an independent contractor.

Menholt Farms, amicus Minnesota Defense Lawyers Association, and amici Chamber of Commerce of the United States of America and the Minnesota Chamber of Commerce (collectively "Chamber of Commerce") argue that recognizing the claim will create tension with the general rule that principals are not liable for the actions of their independent contractors. See Lamb v. S. Unit Jehovah's Witnesses, 45 N.W.2d 403, 406 (Minn. 1950) ("As a general rule, an employer is not liable for the acts of an independent contractor or his servants.").

A principal is also liable for the negligent performance of a nondelegable duty by an independent contractor. Lamb v. South Unit Jehovah's Witnesses, 232 Minn. 259, 45 N.W.2d 403 (1950). Liability, however, follows only upon a finding that the act causing injury was within the scope of the agency.

The general rule is that an employer is not liable for injuries caused by the negligence of an independent contractor. See Annot., 33 A.L.R.2d 7, 18 (1954); Lamb v. South Unit Jehovah's Witnesses, 232 Minn. 259, 45 N.W.2d 403 (1950). However, this court has long recognized an exception to this rule when the employer engages the independent contractor to perform inherently dangerous work.