Dust Almanac

Obeche

Triplochiton scleroxylon · Malvaceae · hardwood

Also known as: samba, wawa, ayous, abachi, African maple

Region: West and Central Africa

Planed board of obeche with pale creamy-yellow wood and a faint ribbon stripe from interlocked grain.

A light, soft, pale cream to straw-colored hardwood that is easy to cut and carve. Widely used for model making, sauna benches and panelling, mouldings, picture frames, and as a core or veneer wood.

Health hazards

  • Asthma / respiratory allergy

    Evidence: Confirmed in clinical testing

    Obeche is one of the best documented wood causes of allergic occupational asthma. Many workers have been confirmed by bronchial challenge plus skin or IgE tests, including a Finnish series in which 27 of 34 symptomatic workers had a positive challenge.12345

    Effects
    asthma, rhinitis, conjunctivitis
    Exposure route
    inhalation
    From
    dust

  • Skin allergy

    Evidence: Confirmed in clinical testing

    Hives where the wood or dust touches the skin have been confirmed in obeche-allergic workers with rubbing tests and specific IgE. People with obeche asthma may also react through the skin.67

    Effects
    contact urticaria (hives)
    Exposure route
    skin
    From
    dust

  • Skin irritation

    Evidence: Listed by an agency

    HSE lists skin irritation, nettle rash, and dermatitis from handling obeche articles.8

    Effects
    skin irritation, dermatitis, nettle rash
    Exposure route
    skin
    From
    dust

  • Respiratory irritation

    Evidence: Listed by an agency

    HSE also lists irritation of the airways, sneezing, wheezing, and feeling feverish among reported effects of obeche dust.8

    Effects
    respiratory tract irritation, sneezing, wheezing, feverishness
    Exposure route
    inhalation
    From
    dust

  • Cancer

    Evidence: Applies to all wood dust

    IARC classifies all wood dust as carcinogenic to humans, chiefly through cancers of the nose and sinuses. This applies to obeche dust as it does to any other wood.9

    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

Known compounds

  • Trip s 1 (38 kDa class I chitinase): major protein allergen source
  • thaumatin-like protein (24 kDa) and gamma-expansin (12 kDa): protein allergens recognized by symptomatic workers source

Cross-reactivity has been shown between obeche and ramin (Hinojosa-1986) and with natural rubber latex (Venturini-2004, Kespohl-2005). One obeche-allergic carpenter had anaphylaxis to tamarillo fruit (Vidal-2006). Obeche from Cameroon (ayous) was found to contain less of the major allergen than obeche from Ghana (wawa) (Kespohl-2008).

Sources

  1. Hinojosa M, Moneo I, Dominguez J, Delgado E, Losada E, Alcover R. Asthma caused by African maple (Triplochiton scleroxylon) wood dust. J Allergy Clin Immunol. 1984;74(6):782-786. Link
  2. Hinojosa M, Losada E, Moneo I, Dominguez J, Carrillo T, Sanchez-Cano M. Occupational asthma caused by African maple (Obeche) and Ramin: evidence of cross reactivity between these two woods. Clin Allergy. 1986;16(2):145-153. Link
  3. Reijula K, Kujala V, Latvala J. Sauna builder's asthma caused by obeche (Triplochiton scleroxylon) dust. Thorax. 1994;49(6):622-623. Link
  4. Ferrer A, Maranon F, Casanovas M, Fernandez-Caldas E. Asthma from inhalation of Triplochiton scleroxylon (Samba) wood dust. J Investig Allergol Clin Immunol. 2001;11(3):199-203. Link
  5. Hannu T, Lindstrom I, Palmroos P, Kuuliala O, Sauni R. Prediction of obeche wood-induced asthma by specific skin prick testing. Occup Med (Lond). 2013;63(6):429-431. Link
  6. Hinojosa M, Subiza J, Moneo I, Puyana J, Diez ML, Fernandez-Rivas M. Contact urticaria caused by Obeche wood (Triplochiton scleroxylon). Report of eight patients. Ann Allergy. 1990;64(5):476-479. Link
  7. Kanerva L, Tuppurainen M, Keskinen H. Contact urticaria caused by obeche wood (Triplochiton scleroxylon). Contact Dermatitis. 1998;38(3):170-171. Link
  8. 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
  9. 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
  10. US Occupational Safety and Health Administration. Occupational Chemical Database: Wood Dust. Last updated 06/23/2023. Link
  11. Kespohl S, Sander I, Merget R, Petersen A, Meyer HE, Sickmann A, Bruening T, Raulf-Heimsoth M. Identification of an obeche (Triplochiton scleroxylon) wood allergen as a class I chitinase. Allergy. 2005;60(6):808-814. Link
  12. Aranda A, Campo P, Palacin A, Dona I, Gomez-Casado C, Galindo L, Diaz-Perales A, Blanca M. Antigenic proteins involved in occupational rhinitis and asthma caused by obeche wood (Triplochiton scleroxylon). PLoS One. 2013;8(1):e53926. Link

Last reviewed .