Numerous witnesses reported strong, unpleasant chemical odors around the plants, particularly on the North part of the industrial area. Figure 5 (next page) shows the distribution of these witnesses. Smells of ammonia and urine were stronger and more aggressive than usual or than ever before. During the morning, the industrial site became increasingly polluted. A witness saw a dense, hazy polluted atmosphere with a fog bank over the SNPE side of the river and above the chimney of this plant (2). Another one saw a thick, white plume of condensed vapor flowing from the prilling tower and drifting horizontally westward (3). This was likely a plume of condensed AN brine kept close to the ground by the thermal inversion and pushed by the Autan wind toward the high voltage line. Around 10:10 am, a witness (4) saw a light grey cloud,