Section 111.33 - Age; exceptions and special cases(1) The prohibition against employment discrimination on the basis of age applies only to discrimination against an individual who is age 40 or over.(2) Notwithstanding sub. (1) and s. 111.322, it is not employment discrimination because of age to do any of the following: (a) To terminate the employment of any employee physically or otherwise unable to perform his or her duties.(b) To implement the provisions of any retirement plan or system of any employer if the retirement plan or system is not a subterfuge to evade the purposes of this subchapter. No plan or system may excuse the failure to hire, or require or permit the involuntary retirement of, any individual under sub. (1) because of that individual's age.(d) To apply varying insurance coverage according to an employee's age.(e) To exercise an age distinction with respect to hiring an individual to a position in which the knowledge and experience to be gained is required for future advancement to a managerial or executive position.(f) To exercise an age distinction with respect to employment in which the employee is exposed to physical danger or hazard, including, without limitation because of enumeration, certain employment in law enforcement or fire fighting.(g) To exercise an age distinction under s. 343.12(2) (a) and (3).1981 c. 334; 1983 a. 391, 538. Sub. (2) (f) exempts the hiring of fire fighters from being the subject of age discrimination suits. A fire department need not show that it openly and consistently discriminated on the basis of age to be exempt under sub. (2) (f). Johnson v. LIRC, 200 Wis. 2d 715, 547 N.W.2d 783 (Ct. App. 1996), 95-2346. An employee is physically unable to perform a job under sub. (2) if that employee is performing the job with a physical accommodation. Harrison v. LIRC, 211 Wis. 2d 681, 565 N.W.2d 572 (Ct. App. 1997), 96-1795. A city charged under the federal Age Discrimination in Employment Act had the burden of establishing that a mandatory retirement age of 55 for law enforcement personnel was a bona fide occupational qualification. Equal Employment Opportunity Commission v. City of Janesville, 630 F.2d 1254 (1980). The federal Employment Retirement Income Security Act preempts sub. (2) (b) to the extent that it applies to employee benefit plans covered by it. Waukesha Engine Division v. DILHR, (1985).