An employer in Maryland may not require or demand, as a condition of employment, prospective employment, or continued employment, that an individual submit to or take a lie detector or similar test. For purposes of this law, an employer is (1) a person engaged in a business, industry, profession, trade or other enterprise in the state; (2) the state; (3) a county; and (4) a municipal corporation in the state, but not the federal government or any of its units.