Iodine Reserves

Although seawater is the world’s largest iodine reserve, with around 34.5 million tons, no economical direct extraction is feasible because of the extremely low concentrations of this element (less than 0.05 ppm).

The main reserves of iodine in brines or caliche ore are in Japan, Chile, USA, Turkmenistan, Azerbaijan and Indonesia. Iodine is also obtained as a by-product in the processing of sodium alginate, mainly in China. Not more than 2% of total iodine consumption is derived from this source. Due to the renewable nature of this raw material, total reserves are not possible to calculate.

Japan’s iodine is found in brines associated with gas wells. Deposits are located in five different zones: Chiba, Niigata, Sadowara, Okinawa and Oshamambe. Actually, only the first three zones are producing, with Chiba, by itself, responsible for 80% of Japan’s total production.

Iodine from Chile is produced from Caliche Ore, mined in the Atacama Desert of northern Chile and west of the Andes Mountains. The Atacama Desert is known as the driest of the world’s deserts, where measurable rainfalls (1 mm or more) may be as infrequent as once every 5 to 29 years. The caliche deposits occupy an area averaging 700 km in a north-south direction by 30 km in an east-west direction.

All current commercial production of iodine in the US comes from deep well brines in northern Oklahoma (mostly from the area known as the Woodward Trench). Historically, commercial iodine production did occur in other states (California, Louisiana and Michigan), but all of those sites have been abandoned for economic and/or environmental reasons.

Iodine production in the Community of Independent States is concentrated in two areas: Turkmenistan (Cheleken, Nebit Dag), and Azerbaijan (Neftchala). In the past iodine was also derived in Russia (Krasnodar), associated with oil extraction, but these operations seem to be closed nowadays. Production in Azerbaijan and Turkmenistan is not associated with oil extraction, their wells were specifically drilled for brine to produce iodine. Iran and Uzbekistan have also been reported to produce iodine from brines but information on current activities is hard to find.

Iodine exploitation in Indonesia comes from brine typically not associated with gas or oil. Deposits are located in Mojokerto, East Java. Production is limited and mainly consumed domestically.


Table: estimated iodine reserves per region

Sources: 2016 USGS Mineral Commodity Summary.

Origin Region Reserves x1000 ton
Underground brines Japan 5000
USA 250
Indonesia 100
Azerbaijan, Russia
Caliche Ore Chile 1800
Seaweed China 4
Total estimated reserves 7514