The Periodic Table of Scarcity and Abundance Fe Iron
Menu

Iron: Harm to health and the planet

What harm does getting and using it do to bodies and the environment?

Steelmaking emits about 2.6 billion tonnes of carbon dioxide a year, about 7% of energy-system emissions, mostly from coal used to smelt ore. Two tailings dam failures at Brazilian iron ore mines killed 289 people. Lack of iron is the most common nutrient deficiency.

Last updated 3 October 2026.

Environmental footprint

Emissions

2.2kg CO₂e per kg1

2024. Crude steel, not pure iron: 2.18 t CO₂e per t of crude steel, average of the companies that report to worldsteel (about half of world output).

Energy

21MJ per kg1

2024. Crude steel: 20.95 GJ per t, worldsteel reporting companies.

Among heavy industries, iron and steel emit the most carbon dioxide2. The IEA put the sector’s direct emissions at 2.6 billion tonnes of CO₂ a year. This is 7% of the total from the energy system2. worldsteel also counts indirect emissions and other greenhouse gases. On that basis the sector emitted about 4.1 billion tonnes of CO₂-equivalent in 2024, 7 to 8% of all human greenhouse gas emissions3. Coal gives about 75% of the sector’s energy2.

Companies that report to worldsteel make about half of the world’s steel. In 2024 they emitted 2.18 tonnes of CO₂-equivalent and used 20.95 gigajoules of energy per tonne of crude steel1. They withdrew 8.5 cubic metres of fresh water per tonne and consumed 2.31. Steel made from scrap needs about one eighth of the energy of steel made from ore2.

Mines leave tailings, the fine waste from concentrating ore, often stored behind dams. In 2015 the Fundão dam failed near Mariana, Brazil. It killed 19 people and polluted the whole Rio Doce basin4. In 2019 a dam at Brumadinho failed and killed 270 people. It was an upstream dam, built in steps on its own tailings5. The human cost is in the society chapter.

Health and the body

Iron is essential for humans. An adult body holds about 3.5 to 4 grams of iron. Most of it is in hemoglobin, the protein in red blood cells that carries oxygen6. Iron deficiency is the most common nutritional deficiency in the world7. The WHO estimates that 40% of children aged 6 to 59 months have anaemia. So do 37% of pregnant women and 30% of women aged 15 to 49. The WHO names dietary iron deficiency as one of the largest causes8.

In the United States the recommended intake for men and for women after menopause is 8 mg a day. For women before menopause it is 18 mg a day. The upper limit for adults is 45 mg a day7.

Too much iron is also harmful. Accidental overdose of iron products is the largest single cause of poisoning deaths in children under six7. In 1997 the US Food and Drug Administration required unit-dose packaging of iron supplements. Known deaths in this age group fell from 29 in the ten years before the rule to 1 in the five years after it9. In hereditary hemochromatosis, the body absorbs too much iron. The iron builds up in organs and is linked to liver cancer and type 2 diabetes7.

At work, iron oxide fume comes from heating iron, for example in arc welding. Repeated exposure can cause siderosis, a lung disease with cough, shortness of breath and changes on chest X-rays10. The US legal limit (OSHA) is 10 mg per cubic metre of air over an 8-hour shift. NIOSH recommends 5 mg over a 10-hour shift10.

Sources

  1. 1

    World Steel Association (worldsteel), the steel industry's association, 2026. World Steel in Figures 2026 , Sustainability indicators; Top 50 companies; Major steel-producing countries; Production by process; Pig iron; DRI; Iron ore 2024; Steel use by sector (p. 30).

    Crude steel, pig iron and DRI output by country, top companies, iron ore trade, emissions and energy per tonne of steel.

    • 2.18 tonnes of CO2e emitted per tonne of crude steel
    • 20.95 GJ of energy consumed per tonne of crude steel
    • 51% of global crude steel production … 2.18 tonnes of CO2e emitted per tonne of crude steel … 20.95 GJ of energy consumed per tonne of crude steel
    • 8.50 m3 of fresh water withdrawn per tonne of crude steel … 2.30 m3 of fresh water consumed per tonne of crude steel
  2. 2

    International Energy Agency, 2020. Iron and Steel Technology Roadmap: Towards more sustainable steelmaking , Executive summary.

    Sector CO2 emissions (2.6 Gt, 7% of the energy system), coal use, scrap share and energy, demand projection to 2050.

    • Among heavy industries, the iron and steel sector ranks first when it comes to CO 2 emissions
    • The iron and steel sector directly accounts for 2.6 gigatonnes of carbon dioxide … 7% of the global total from the energy system
    • the largest industrial consumer of coal, which provides around 75% of its energy demand
    • Steel production from scrap requires around one-eighth of the energy of that produced from iron ore
  3. 3

    World Steel Association (worldsteel), 2025. Climate change and the production of iron and steel , Keeping track of our emissions.

    Steel sector emissions of about 4.1 billion t CO2e in 2024 (scopes 1 to 3), 7 to 8% of global anthropogenic greenhouse gas emissions.

    • total emissions from our sector were of the order of 4.1 billion tonnes … These emissions represent 7% – 8% of global anthropogenic GHG emissions
  4. 4

    Ministério Público Federal (Brazil's federal prosecution service, which brought the appeal), 2026. TRF6 condena Samarco e três ex-gerentes por rompimento de barragem em Mariana (MG) .

    The TRF6 appeal ruling of September 2026 against Samarco and three former managers, as reported by the prosecutor (in Portuguese). Deaths, harm to the Rio Doce basin and losses of the towns.

    • provocou destruição ao longo de toda a bacia do Rio Doce … Houve 19 mortes
  5. 5

    Zhu F., Zhang W., Puzrin A.M. (Communications Earth & Environment), 2024. The slip surface mechanism of delayed failure of the Brumadinho tailings dam in 2019 , Abstract; Introduction.

    Brumadinho dam failure on 25 January 2019, 270 deaths, and the link to the 2015 Fundão failure.

    • failed suddenly, killing 270 people … The Feijão dams was built in the upstream manner
  6. 6

    Uwitonze A.M., Murererehe J., Rehman M., Chittilla M. and others (Frontiers in Nutrition), 2023. Oral manifestations of iron imbalance , Introduction; Iron metabolism.

    Body iron of about 4.0 g in men and 3.5 g in women, and its share in hemoglobin and myoglobin.

    • Body iron content is approximately 4.0 gm in men and 3.5 gm in women … The majority of iron (60–70%) is in the hemoglobin
  7. 7

    Linus Pauling Institute, Oregon State University, 2026. Iron (Micronutrient Information Center) , Summary; Safety, Toxicity; Table 3.

    Recommended intakes, upper limit, child poisoning, hemochromatosis.

    • Iron deficiency is the most common nutritional deficiency worldwide, affecting primarily children, women of childbearing age, pregnant women
    • 8 mg/day for men and postmenopausal women, 18 mg/day for premenopausal women … The UL for adolescents (14-18 years) and adults, including pregnant and breastfeeding women, is 45 mg/day
    • Accidental overdose of iron-containing products is the single largest cause of poisoning fatalities in children under six years of age
    • hereditary hemochromatosis (HH) has been associated with an increased incidence of liver cancer , type 2 diabetes mellitus
  8. 8

    World Health Organization, 2025. Anaemia (fact sheet) , Key facts.

    Global anaemia prevalence and its causes.

    • 40% of all children aged 6–59 months, 37% of pregnant women and 30% of women 15–49 years of age are affected by anaemia … The largest causes were dietary iron deficiency
  9. 9

    Tenenbein M. (Archives of Pediatrics & Adolescent Medicine), 2005. Unit-dose packaging of iron supplements and reduction of iron poisoning in young children , Abstract (PubMed record 15939855, text format).

    Deaths from iron poisoning in US children under six fell from 29 (1988 to 1997) to 1 (1998 to 2002) after the 1997 unit-dose packaging rule.

    • proclaimed a regulation for unit-dose packaging of iron supplements in 1997 … The 10 years prior to the intervention were compared with the 5 years after its promulgation … The number of deaths decreased from 29 to 1
  10. 10

    New Jersey Department of Health, 2007. Hazardous Substance Fact Sheet: Iron Oxide , Workplace Exposure Limits; Chronic Health Effects (revision of May 2007).

    OSHA and NIOSH workplace limits for iron oxide, and siderosis.

    • Iron Oxide fume is produced when materials containing Iron are heated, as in arc welding … Repeated exposure to Iron Oxide fume or dust can cause pneumoconiosis (Siderosis) with cough, shortness of breath and changes on chest x-ray
    • OSHA: The legal airborne permissible exposure limit (PEL) is 10 mg/m3 averaged over an 8-hour workshift. NIOSH: The recommended airborne exposure limit is 5 mg/m3 averaged over a 10-hour workshift