#1629 1924 · Morton Salt Company · Food / public health
Morton Salt didn't want to run two product lines — so it iodized everything
the problem
A health fix needed in one region meant running a separate, costlier product line just for that market
background
By the early 1920s the region around the Great Lakes, particularly Michigan, was widely known as America's "goiter belt," where iodine-deficiency-related thyroid swelling ran so high that during World War I Michigan draft boards had turned away large numbers of young men for exactly this condition, in some areas affecting as much as 64% of the population. David M. Cowie, a University of Michigan pediatrics professor familiar with Swiss public health practice, recommended iodizing table salt as a near-universal, low-cost delivery mechanism, and on March 15, 1924 the Michigan State Medical Society formally voted to recommend salt containing a small measured percentage of sodium iodide.
Morton Salt Company initially resisted supplying iodized salt to Michigan specifically, reportedly concerned about the added cost and operational complexity of manufacturing, packaging and distributing a separate iodized product line solely for one regional market rather than continuing its existing single national product.
what everyone would do
Supply the iodized version specifically to Michigan and other goiter-belt markets that requested it, continuing to manufacture and sell the standard formulation everywhere else, treating this as a straightforward regional product segmentation decision rather than reconsidering the company's entire national product line.
what they saw
Morton didn't want a special line just for Michigan's goiter problem — that meant running two products. So it iodized everything nationwide. One line was cheaper than two, and it happened to end a public health crisis.
the move
Rather than build and maintain two parallel salt product lines indefinitely, one iodized for Michigan and the goiter belt, one plain for the rest of the country, Morton Salt made the calculation that a single universal formulation was operationally simpler and cheaper to manufacture and distribute than segmenting its national product line for one region's specific health need, so several months after the first iodized salt appeared in Michigan stores on May 1, 1924, Morton rolled iodization out as the default nationwide rather than as a regional variant. This decision meant the health intervention reached the entire country simultaneously, not because of a deliberate national public health campaign, but as a byproduct of a straightforward manufacturing and distribution cost calculation that happened to align with broad public benefit: within months more than 90% of table salt sold in Michigan was iodized, and the practice, once made the national default rather than an opt-in regional product, became so unremarkable that within a generation American iodine deficiency and its associated goiter rates fell dramatically, an outcome subsequent economic research, including a National Bureau of Economic Research working paper on the long-run impacts of salt iodization, has credited with measurable downstream effects on cognitive development and adult economic outcomes for the generation born after the rollout.
why it works
The universal-default approach worked because for a commodity product manufactured and distributed at national scale, the fixed cost of maintaining an entirely separate production and distribution line for one regional market often exceeds the marginal cost of simply upgrading the single national formulation, especially once the additive itself, iodine, was cheap relative to the product's overall cost. Making the healthier version the default also meant reaching everyone automatically without requiring individual consumers anywhere to seek out, choose or pay a premium for the improved version, a reach a targeted, opt-in regional product could never achieve on its own.
the payoff
After resisting a Michigan-only iodized line, Morton made iodized salt the national default in 1924 — one line was cheaper than two.
where it breaks
This mechanism only makes operational sense when the added ingredient or process change is cheap enough relative to the base product that eliminating segmentation genuinely saves money rather than raising costs everywhere for a benefit only some customers need; a change with meaningful added cost per unit could make maintaining separate product lines the more rational choice despite the added complexity. It also depends on the universal change carrying no meaningful downside or objection from customers who don't need the intervention, since making something the default for everyone removes the ability of unaffected customers to opt out.
what came after
Credited by subsequent economic research, including a National Bureau of Economic Research working paper, with measurable long-run improvements in cognitive development and adult economic outcomes for the generation born after the national rollout, and remains a widely cited public health case study for how a single universal default can achieve population-scale reach a targeted regional program cannot.
references
- [1]The Long-run Economic Impacts of Salt Iodization in the United StatesNational Bureau of Economic Research, 2018nber.org
- [2]A Grain of SaltMilbank Quarterly, Milbank Memorial Fund, 2019milbank.org