The purpose of these studies is to identify possible candidate industries, labor unions and workplaces with occupational exposures to welding fumes (WF) with special emphasis on manganese (MN) and recruit their participation in an exposure assessment study. NIOSH has identified a specific need for assessing the neuropsychiatric effects of WF, as concern was noted for the potential of manganese (Mn) in welding fume to cause neurotoxicity in exposed workers. This study will measure workplace exposures of welders, especially those exposed to appreciable levels of Mn, often associated with mild-steel and stainless steel welding operations. Manganese in WF complexes with many other metal elements, chiefly iron, oxides, and fluoride and may exist in several valence states. A literature review and initial field surveys are ongoing to assemble the information necessary to more thoroughly develop the study design and exposure monitoring strategy. Selection of sites will depend on the: industrial sector;welding process(es);production rates;number of welders and other workers exposed;previous exposure records;anticipated exposure levels (preferably with a range of exposures);and work place conditions. A notice was posted on the NIOSH e-news internet site which solicited partnerships with the private sector to allow NIOSH access to their sites where welding activities occur to evaluate workers? exposures to WF with emphasis on Mn. This posting resulted in several companies interested in participating in the study. Contact with key management personnel was initiated and site visits are scheduled at three facilities. These walk through surveys will collect supporting information, introduce the project to plant and union representatives, and collect a series of ?screening? samples to aid in the analytical method development and experimentation. Furthermore, research regarding the particle size distributions of WF may also be conducted by using direct reading instrumentation which should include nanometer particle size screening. The Chemical Exposure and Monitoring Branch at NIOSH has begun research to investigate methods development for characterizing the different forms of Mn in welding fume air samples collected in industrial hygiene field surveys where contaminant mass loading may be low. This endeavor is the first phase of a more comprehensive exposure assessment study with the intent to expand the worker population into an occupational cohort for future epidemiological studies.
