Drive closer and the sharp white peaks turn out to be a small Alps of salt — the Aral Tuz Company stockpile. Salt has been dug here for centuries. Nowadays, a great rail-mounted combine chews away at a 10-foot-thick layer of salt in the old seabed, before it is towed 11 miles back to the plant, and washed and ground. Before it reaches the packaging room, as the salt falls through a chute from one conveyor belt to another, a small pump sprays iodine into the grainy white cascade. The step is so simple that, if it were not for the women in white lab coats scooping up samples, it would be missed.

The $15,000 tank and sprayer were donated by Unicef, which also used to supply the potassium iodate. Today Aral Tuz and its smaller rival, Pavlodar Salt, buy their own.

Asked about the Unicef report saying that Aral Tuz initially resisted iodization on the grounds that it would eat up 7 percent of profits, the company’s president, Ontalap Akhmetov, seemed puzzled. “I’ve only been president three years,” he said. “But that makes no sense.” The expense, he said, was minimal. “Only a few cents a ton.”

Kazakhstan was lucky. It had just the right mix of political and economic conditions for success: political support, 98 percent literacy, an economy helped along by rising prices for its oil and gas. Most important, perhaps, one company, Aral Tuz, makes 80 percent of the edible salt.

That combination is missing in many nations where iodine deficiency remains a health crisis. In nearby Pakistan, for instance, where 70 percent of households have no iodized salt, there are more than 600 small salt producers.

“If a country has a reasonably well-organized salt system and only a couple of big producers who get on the bandwagon, iodization works,” said Venkatesh Mannar, a former salt producer in India who now heads the Micronutrient Initiative in Ottawa, which seeks to fortify the foods of the world’s poor with iodine, iron and other minerals. “If there are a lot of small producers, it doesn’t.”

Now that Kazakhstan has its law, Ms. Sivryukova’s volunteers have not let up their vigilance. They help enforce it by going to markets, buying salt and testing it on the spot. The government has trained customs agents to test salt imports and fenced some areas where people dug their own salt. Children still receive booklets and instruction.