The Council of the European Union is an Institution with a formal legislative role. It is composed of different configurations of national Ministers (one per country). The exact configuration of each meeting depends upon the topic under discussion. Generally in the ENVI Council, Ireland is represented by Minister for the Environment, Community and Local Government, Phil Hogan TD.
For more information, please see: http://www.eu2013.ie/events/event-items/meetingofenvironmentcouncilenvi-20130321/