I.-Employers with at least fifty employees, including the companies and public establishments mentioned in articles L. 2211-1 and L. 2233-1 employing at least fifty employees, as well as companies belonging to a group within the meaning of article L. 2331-1 whose workforce includes at least fifty employees, begin negotiations on an agreement to prevent the effects of exposure to the occupational risk factors mentioned in article L. 4161-1:
1° Or when they employ a minimum proportion, set by decree, of employees declared to be exposed under the system mentioned in article L. 4163-1 ;
2° Or when their accident rate for accidents at work and occupational illnesses exceeds a threshold under conditions defined by decree.
II.-Companies with a workforce of at least fifty and less than three hundred employees or belonging to a group within the meaning of article L. 2331-1 with a workforce of less than three hundred employees are not obliged to conclude an agreement mentioned in I of this article or an action plan mentioned in article L. 4162-2 if they are already covered by an extended branch agreement including the themes mentioned in 1° of article L. 4162-3.