var imageFiles_z_19 = new Array();
imageFiles_z_19['0'] = new Array ('_images/z_ENVIRONMENTAL_FACTS.gif', '_images/z_ENVIRONMENTAL_FACTSMouseover.gif');

function image_on_z_19 (position) {
   var doc = eval("document.imagez_19" + position);
   doc.src = imageFiles_z_19[position][1];
}

function image_off_z_19 (position) {
   var doc = eval("document.imagez_19" + position);
   doc.src = imageFiles_z_19[position][0];
}