No abstract

The National Institute for Occupational Safety and Health (NIOSH) conducted 21 field surveys in selected industries to characterize workers' exposures to hexavalent chromium-containing airborne particulate and to evaluate existing technologies for controlling these exposures. Hexavalent chromium Cr(VI) is a respiratory irritant and chronic inhalation may cause lung cancer. Primary evaluation methods included collection of full work shift, personal breathing-zone (PBZ) air samples for Cr(VI), measurement of ventilation system parameters, and documentation of processes and work practices. This study emphasized evaluation of engineering exposure control measures, so PBZ exposures were measured on the outside of personal protective equipment, for example, respirators. Field surveys were conducted in two chromium electroplating facilities, including one where full-shift PBZ exposures to Cr(VI) ranged from 3.0 to 16 times the 1 micro g/m(3)NIOSH recommended exposure limit (REL) despite several engineering controls on the plating tanks. At a painting and coating facility that used Cr(VI)-containing products, full-shift exposures of painters and helpers (2.4 to 55 micro g/m(3)) exceeded the REL, but LEV effectiveness was limited. Other operations evaluated included welding in construction; metal cutting operations on chromium-containing materials in ship breaking; chromate-paint removal with abrasive blasting; atomized alloy-spray coating; foundry operations; printing; and the manufacture of refractory brick, colored glass, prefabricated concrete products, and treated wood products. NIOSH researchers concluded that, in many of the evaluated processes, Cr(VI) exposures at or below the current NIOSH REL are achievable. However, for some processes, it is unclear whether controlling exposures to this range is consistently achievable without respirator use. Some operations involving the application of coatings and finishes may be among those most difficult to control to this range. Most operations judged to be moderately difficult to control to this range involve joining and cutting metals with relatively high chromium content. Nonetheless, exposures in a wide variety of other processes were judged more easily controllable to the current REL or below, or were found to be minimal, including some operations meeting the general descriptions named above but with different specific operating parameters producing lower Cr(VI) exposures.

No abstract

One of the key issues involved in the development of passive optical power limiters is the search for appropriate materials that show effective reverse saturable absorption. metallophthalocyanines seem to be good candidates for such applications because of their higher optical nonlinearity and the unique electronic absorption characteristics. A series of 1 ,4,8, 1 1 ,15 ,18,22,25-octa-decyloxy metallophthalocyanines containing various central metal atoms such as zinc, copper, palladium, nickel, and cobalt were characterized for their nonlinear absorptive properties to evaluate their suitability to function as reverse saturable absorbers. Nonlinear transmission measurements were analyzed in terms of five-state model and magnitudes of the parameters of the model were determined.

The modification updates the facility contact and address information, and the process codes and design capacity section for Technical Area (TA) 14; TA-16; TA-39; TA-54 West; TA-54, Area G; and TA-55 within the Attachment B, Part A Application. The process codes and design capacity section for TA-14, TA-16, and TA-39 was updated to incorporate a statement that the Permittees have notified of the intent to close units at these locations. The process design capacity for TA-54, Area G has been updated from 3,664,150 gallons to 4,346,590 gallons to account for the TA-54, Area G Pad 11 container storage unit that was added when the Permit was issued in 2010 but at the time did not previously store hazardous waste. The number of units at TA-54, Area G was also updated to 9 units to include this new unit. The process design capacity for TA-55 has also been updated from 178,500 gallons to 207,600 gallons to incorporate the addition of the TA-55-185 container storage unit that was also added when the Permit was issued. The number of storage units at TA-55 was updated to 7 to include the unit. The process design capacity at TA-54 West was changed to 11,660 gallons to correct a typographical error in previous versions of the form. Basis These changes must be made to the form to ensure it is up-to-date and can be certified as "true, accurate, and complete" as required by 40 CFR § 270.11(d) and as stated on the signature line of the Part A form. The new revision (10.0) of the Part A Application is classified as an administrative change pursuant to 40 CFR § 270.42, Appendix I, Item A.1, because no changes in requirements are proposed; only information updates to the application.