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Published byDominick Hessell Modified over 9 years ago
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Chromates (Hexavalent Chromium) ASSE ASSE Region III Professional Development Conference Austin, Texas August 7, 2006 Frank M Parker, III CIH, CSP, PE, DEE
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Chromates Chrome Compounds –Chrome (II) CrF 2 Green CrCl 2 White CrBr 2 White CrI 2 Red-Brown –Chrome (III) CrF 3 Green CrCl 3 Red-Violet CrBr 3 Green-Black CrI 3 Black Cr 2 O 3 Green
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Chromates Chrome Compounds –Chrome (IV) CrO 2 Brown - Black –Chrome (VI) CrO 3 Deep RedK 2 Cr 2 O 7 CaCrO 4 YellowNa 2 Cr 2 O7·2H 2 O PbCrO 4 YellowSrCrO 4 K 2 CrO 4 ZnCrO 4
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Chromates Health Effects –Cr (III) 50 – 200 µg / day Required in Diet Irritation, Dermatitis, Allergies –Cr (VI) Water Soluble –Liver, Kidney, Respiratory Insoluble –Cancer, Irritation
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Chromates Where Chromates (VI) Are Found –Pigments (paints, inks, & plastics) –Spray Coatings –Stainless Steel –Electroplating & Metal Cleaning –Corrosion Inhibitors –Wood Preservatives –Tanning –Textiles Dyes –Chromate Production
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Chromates Some Occupations at Risk –Petrochemical Workers (III & VI) –Welders (VI) –Painters (III & VI) –Copy Machine Toners (VI) –Battery Makers (VI) –Candle Makers (III & VI) –Dye Makers (III) –Printers (III & VI) –Rubber Makers (III & VI) –Cement Workers (III & VI)
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Chromates Exposure Concentrations (ATSDR) –Stainless Steel Welding: 50 – 400 µg/m 3 –Ferrochrome Alloys: 10 – 140 µg/m 3 –Chrome Pigments: 60 – 600 µg/m 3 –Aircraft Production: 0.02 – 1.5 µg/m 3
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Chromates Chrome (VI) with OELs ( mg/m3 ) ACGIHNIOSHOSHA Cr +6 Compound TWASTELTWASTELTWASTEL tert-Butyl chromate- 0.1 (CrO 3 ) 0.001 Cr (VI) -- 0.1 (CrO 3 ) Calcium chromate 0.001 (Cr) ----- Chromic Acid & Chromates -- 0.001 (CrO 3 ) -- Chromium (VI) Compounds 0.05 w 0.01 i -0.001-0.005- Lead chromate 0.012 (Cr) ----- Strontium chromate 0.0005 (Cr) -----
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Chromates OSHA’s Final Rule Published: February 28, 2006 Effective Date: + 90 days Start up Date: 180 days (1 year for Employers < 20 Workers) Engineering Controls: 4 years
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Chromates Permissible Exposure Limits Chromium (VI) in any form or compound AL = 2.5 µg/m 3 (8 hr. TWA) PEL = 5 µg/m 3 (8 hr. TWA) Aircraft Industry: 25 µg/m 3 + RPE Portland Cement & Pesticides: NA
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Chromates IH Sampling –8hour TWA: Sufficient Number of Samples Each Employee Full Shift Each Shift Each Job Class Each Work Area Accuracy For Concentrations ≥ A.L. –Monitoring & Analysis Accuracy = ±25% –Accurate Measurements = 95% C.L.
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Chromates Analytical Methods Method #MediaAnaliteLODAccuracy NIOSH 7600AirCr +6 0.05 µg± 18.58 % NIOSH 7604Air Cr +6 3.5 µg ± 13 % NIOSH 9101DustCr +6 1 µg ? NIOSH 7024AirTotal Cr 0.06 µg ± 20.91 % OSHA ID-215AirCr +6 3 µg ±12.9 % NIOSH 7605Air Cr +6 0.02 µg ±17.4 %
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Chromates Scientific Challenges –Sampling; Enough volume for LOD –Analysis Quantifying Concentrations of Metals (Sr, Pb, Ca, etc) Quantifying Cr +6 –Calculating Exposure Concentrations
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Chromates Calculations –Consume Cr +6 per Hierarchical Method Sr – 0.005 µg/m 3 First; Ca – 0.001 µg/m 3 Next; tBCr – 0.001 µg/m 3 Next; Pb – 0.012 µg/m 3 Last.
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Chromates Program Challenges –Finding Chromates in the workplace; –Selling the effort necessary to quantify exposures; –Maintaining program for all future use of chromates; –Dealing with PR issues surrounding historical exposures; –Meeting the statistical standards; –Finding substitutes; –Implementing appropriate controls; –Keeping your program between OSHA, ACGIH, NIOSH, etc. and the current state of art and science.
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Chromates Mother Nature Doesn’t Give a Dam! People don’t do what you expect them to do, they do what you inspect them to do. Good safety programs are not free. A significant percentage of your workers will get cancer! Cancer is not free; someone will pay the bill. The only question is who? Time is of the essence.
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