Dust Almanac

Iroko

Milicia excelsa · Moraceae · hardwood

Also known as: African teak, odum, mvule, kambala, Milicia excelsa, Chlorophora excelsa

Region: Tropical Africa, from West Africa to East Africa

Planed board of iroko with yellowish golden-brown heartwood, coarse open grain and a narrow band of pale sapwood.

Iroko is a durable, yellow-brown African hardwood that darkens with age and is often used as a cheaper substitute for teak. Woodworkers use it for outdoor furniture, boat work, worktops, joinery and flooring.

Health hazards

  • Asthma / respiratory allergy

    Evidence: Confirmed in clinical testing

    Iroko dust is a confirmed cause of occupational asthma. In an Italian study all nine affected woodworkers had asthma reactions when challenged with iroko dust in the clinic, and a Spanish case was confirmed the same way.1234

    Effects
    asthma
    Exposure route
    inhalation
    From
    dust

  • Hypersensitivity pneumonitis

    Evidence: Listed by an agency

    The UK safety regulator names iroko as one of the woods that can rarely cause allergic alveolitis, a flu-like lung inflammation that can lead to lasting lung damage.4

    Effects
    extrinsic allergic alveolitis
    Exposure route
    inhalation
    From
    dust

  • Skin allergy

    Evidence: Listed by an agency

    Dermatitis from iroko is listed by the UK safety regulator, and case reports describe allergic skin rashes from iroko dust, including on the face from airborne dust.456

    Effects
    dermatitis, allergic contact dermatitis
    Exposure route
    skin
    From
    dust

  • Skin irritation

    Evidence: Listed by an agency

    The UK safety regulator lists nettle rash (hives) among the reported effects of iroko.4

    Effects
    contact urticaria (hives)
    Exposure route
    skin
    From
    dust

  • Cancer

    Evidence: Applies to all wood dust

    IARC classifies all wood dust as carcinogenic to humans, mainly linked to cancers of the nasal cavity and sinuses after long-term exposure.7

    Effects
    nasal and sinus cancer
    Exposure route
    inhalation
    From
    dust

Not finding a hazard listed here does not mean this wood is safe. All wood dust is hazardous; see how to protect yourself.

Exposure limits

Workplace exposure limits (8-hour average, mg/m³)
BodyLimitNotes
ACGIH TLV1 mg/m³ (inhalable) source
EU binding limit (hardwood)2 mg/m³Applies to all hardwood dust
UK WEL (hardwood)3 mg/m³Applies to all hardwood dust
NIOSH REL1 mg/m³Recommended limit for all wood dust

Compare limits across agencies.

Cancer classifications

Milicia regia (also traded as iroko) is a close relative; evidence here is reported simply as iroko and may include either species. 'African teak' is a trade name only; iroko is not related to true teak.

Sources

  1. Ricciardi L, Fedele R, Saitta S, Tigano V, Mazzeo L, Fogliani O, Barber D, Isola S. Occupational asthma due to exposure to iroko wood dust. Ann Allergy Asthma Immunol. 2003;91(4):393-397. Link
  2. Azofra J, Olaguibel JM. Occupational asthma caused by iroko wood. Allergy. 1989;44(2):156-158. Link
  3. Pickering CA, Batten JC, Pepys J. Asthma due to inhaled wood dusts: western red cedar and iroko. Clin Allergy. 1972;2(3):213-218. Link
  4. Health and Safety Executive. Toxic woods. Woodworking Information Sheet No 30 (Revision 1), WIS30(rev1). HSE; first published 11/2012. Withdrawn from hse.gov.uk (404 since c. Jan 2020); archived copy cited. Link
  5. Hinnen U, Willa-Craps C, Elsner P. Allergic contact dermatitis from iroko and pine wood dust. Contact Dermatitis. 1995;33(6):428. Link
  6. Stingeni L, Mariotti M, Lisi P. Airborne allergic contact dermatitis from iroko (Chlorophora excelsa). Contact Dermatitis. 1998;38(5):287. Link
  7. IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. Wood Dust and Formaldehyde. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 62. Lyon: International Agency for Research on Cancer; 1995. Link
  8. US Occupational Safety and Health Administration. Occupational Chemical Database: Wood Dust. Last updated 06/23/2023. Link

Last reviewed .