28. Whoever keeps an industrial or commercial establishment contrary to the provisions of this act is guilty of an offence and shall be liable, in addition to costs,(a) in the case of an individual, to a fine of not less than two hundred dollars nor more than six hundred dollars;
(b) in the case of a corporation, to a fine of not less than five hundred dollars nor more than two thousand dollars;
(c) for the first subsequent offence within two years, to a fine the amount of which shall not be less or greater than twice the fines provided for in subparagraph a or b, as the case may be;
(d) for any other subsequent offence within two years, to a fine the amount of which shall not be less or greater than three times the fines provided for in subparagraph a or b, as the case may be.