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Presented by Venetia Runnion, CIH, CSP Field Research and Consultation Group http://depts.washington.edu/frcg/about.html. Occupational Exposure to Hexavalent Chromium in the Maritime Industry Maritime Seminar October 9, 2006. Cr VI Chemical Description.
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Presented by Venetia Runnion, CIH, CSP Field Research and Consultation Group http://depts.washington.edu/frcg/about.html Occupational Exposure to Hexavalent Chromiumin the Maritime IndustryMaritime Seminar October 9, 2006
Cr VI Chemical Description • Chromium metal with a valence of positive 6 • Blue-white to steel gray, lustrous, brittle, hard, odorless solid • Pigments are typically lemon yellow – orange – dark red hues
Maritime Uses of Hexavalent Chromium/Chromates • Welding and thermal cutting • Spray application of corrosion resistant protective coatings • Metal cleaning
Health Effects • Severe irritant of nasopharynx, larynx, lungs and skin • Damage to nasal epithelia and skin (chrome ulcer) • Asthma • Lung cancer
Health Studies on Welders • Metal fume fever • X-ray and lung function changes • 40% increase in risk of lung cancers • Additional cancers • Vision problems
Hexavalent Chromium StandardScope and Application Applies to occupational exposure to chromium (VI) in general industry, construction, and shipyard employment
CrVI Sources • Stainless steel • High chromium nickel alloys • Electrodes • Filler metals • HSLA (high strength low alloy) steels • Tool steels
Welding Processes and Fume Generation Rates (g/min) • FCAW-CO2>1 • FCAW-Ar/CO2 0.6 • GMAW-Steady 0.5 • SMAW 0.4 • GMAW-Pulsed 0.2 • GTAW <0.1 • SAW <0.1
Worker Exposures (μg/m3) • SMAW 0.1 - 150 • FCAW 0.1 - 38 • GMAW 0.1 - 13 • GTAW LDL- 5 • SAW LDL - 0.7 • Plasma cutting 0.1- 20 • Metal cleaning 0.1 - 610
Minimizing exposures • Different welding process • Material substitution • Different shielding gas • Reduce current and voltage
Control measures • Local exhaust ventilation evaluation* • SMAW w/o 0.4 - 34 • SMAW with 0.1 – 40 • Fume extracting guns • PAPR welding helmets * Navy study on LEV effectiveness—looked at SMA welding with same variables—only difference was LEV or no LEV.
References www.nsrp.org: Navy and National Shipbuilding Research Program 1998 published report www.ewi.org/njc: the Edison Welding Institute report contracted by NSRP and published in 2003
Thank you! University of Washington Field Research and Consultation Group http://depts.washington.edu/frcg/about.html