When Arnaud Laillou, a nutrition specialist with UNICEF, led a salt iodization study in 2014, he wanted to be sure that salt producers were not adding too much iodine.

Just four years earlier, UNICEF had stopped providing iodine to salt producers at the end of a decade-long, largely successful government-run iodization program. Laillou was stunned to find that 90 percent of coarse salt and 40-50 percent of fine salt was now not iodized. And all of it was labeled as iodized.