Section 67.25-5 - Obstruction lights(a) The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this part and shall be of sufficient candlepower as to be visible at a distance of at least three nautical miles 90 percent of the nights of the year. The lights shall be displayed not less than 20 feet above mean high water, but not at a height greater than that specified in § 67.05-1(f) , except that on Class "B" structures which are required to be marked by only one light, that light may be displayed not less than 10 feet above mean high water if the structural features preclude mounting the light within the range of heights otherwise specified in this section.(b) The District Commander may waive the requirement for obstruction lights on Class "B" structures if there is no hazard to navigation by so doing.CGFR 58-34, 23 FR 7701, Oct. 4, 1958, as amended by CGFR 62-32, 27 FR 10101, Oct. 13, 1962