Occupational Exposure to Carbon Nanotubes and Nanofibers

••Workers in areas or in jobs who are qualitativelydetermined (by the person chargedwith program oversight) to have the potentialfor exposure to intermittent elevated airborneconcentrations of CNT or CNF (i.e., workersare at risk of being exposed if they are involvedin the transfer, weighing, blending, ormixing of bulk CNT or CNF; or in the cutting,grinding, or drilling of composite materialscontaining CNT or CNF; or in areas wheresuch activities are carried out by others).6.7.2 Program OversightOversight of the medical surveillance programshould be assigned to a qualified health-care professionalwho is informed and knowledgeable aboutpotential workplace exposures, routes of exposure,and potential health effects related to CNT and CNF.6.7.3 Screening ElementsInitial evaluation••An initial (baseline) evaluation should beconducted by a qualified health professionaland should consist of the following:ȣȣȣȣȣȣAn occupational and medical historywith respiratory symptoms assessed byuse of a standardized questionnaire suchas the American Thoracic Society RespiratoryQuestionnaire [Ferris 1978], orthe most recent equivalent.A physical examination with an emphasison the respiratory system.A spirometry test. (Anyone administeringspirometry testing as part of the medicalscreening program should have completeda NIOSH-approved training course in spirometryor other equivalent training; additionally,the health professional overseeingthe screening and surveillance programshould be expert in the interpretationof spirometry testing results, enablingfollow-up evaluation as needed.)ȣȣȣȣA baseline chest X-ray (digital or filmscreenradiograph). All baseline chest imagesshould be clinically interpreted by aboard eligible/certified radiologist or otherphysician with appropriate expertise,such as a board eligible/certified pulmonologist.Periodic follow up chest X-raysmay be considered, but there is currentlyinsufficient evidence to evaluate effectiveness.However, if periodic follow up is obtained,clinical interpretation and classificationof the images by a NIOSH-certifiedB reader using the standard InternationalClassification of Radiographs of Pneumoconioses(ILO 2011 or the most recentequivalent) are recommended.Other examinations or medical testsdeemed appropriate by the responsiblehealth-care professional. (The need forspecific medical tests may be based onfactors such as abnormal findings oninitial examination—for example, thefindings of an unexplained abnormalityon a chest X-ray should prompt furtherevaluation that might include the use ofhigh-resolution computed tomographyscan of the thorax.)Periodic evaluations••Evaluations should be conducted at regularintervals and at other times (e.g., post-incident)as deemed appropriate for the individual workerby the responsible health-care professional.Evaluations should be based on data gatheredin the initial evaluation, ongoing workhistory, changes in symptoms such as new orworsening respiratory symptoms, and whenprocess changes occur in the workplace (e.g.,a change in how CNT or CNF are manufacturedor used or an unintentional spill). Evaluationsshould include the following:ȣȣAn occupational and medical history update,including a respiratory symptom update,and focused physical examination—performed annually.68 NIOSH CIB 65 • Carbon Nanotubes and Nanofibers