Section 521 - County laboratories; establishment by referendum1. Upon the petition signed by two hundred or more taxpayers of the county or district to be served by such a laboratory, the governing body of that county or district at the next date for filling an elective office shall hold a referendum upon the question of establishing a laboratory the construction of which is to be financed by taxes levied for the fiscal year in which the expenditures therefor are to be made. If a majority of the votes cast are in favor of establishing such a laboratory it shall be mandatory upon the governing body of that county or district to take the steps necessary for the establishment and maintenance of such a laboratory as provided for by this chapter.2. Nothing contained in sections five hundred to five hundred twenty-one, inclusive, of this chapter shall be construed to prevent the financing of any expenditure, in whole or in part, pursuant to the local finance law.N.Y. Pub. Health Law § 521