Abstract  Acetylene, C2H2, is a highly reactive, commercially important hydrocarbon. Its reactivity is related to its triple bond between carbon atoms and, as a consequence, its high positive free energy of formation. Because of its explosive nature, long distance shipping or pressurized storage is not recommended. Thus acetylene is generally used as it is produced without shipping or storage. Commercially, acetylene is used primarily as a raw material for the synthesis of a variety of organic chemicals. In the United States, this accounts for ∼90% of acetylene usage, with the balance being used for metal welding and cutting. Worldwide acetylene production peaked in the mid-1960s, after which it declined dramatically as processes were developed to substitute lower cost olefins and paraffins for the acetylene feedstock. 1,4-Butanediol production accounts for 90% of the demand for acetylene for chemical production. Although acetylene production in Japan, China, and Eastern Europe is still based on the calcium carbide process, the large producers in the United States, Western Europe, and Russia now rely principally on the partial oxidation of natural gas. However, much of the incremental growth in production is based on producing acetylene as a coproduct of ethylene in the steam cracking process. As a coproduct, acetylene is much less costly than as produced from partial oxidation or calcium carbide.

Abstract  OBJECTIVES: The exposure of seven workers and three on-site study examiners to N-methyl-2-pyrrolidone (NMP) was studied in an adhesive bonding compound and glue production facility.

METHODS: Airborne NMP was analysed by personal and stationary sampling on activated charcoal tubes. NMP and its main metabolites, 5-hydroxy-N-methyl-2-pyrrolidone (5-HNMP) and 2-hydroxy-N-methylsuccinimide (2-HMSI), were analysed in pre-shift and post-shift spot urine samples by gas chromatography-mass spectrometry. The workers were examined with respect to irritation of the eyes, the mucous membranes and the skin, and health complaints before and after the work-shift were recorded.

RESULTS: The time-weighted average concentration of NMP in most work areas varied between 0.2 and 3.0 mg/m3. During the manual cleaning of stirring vessels, valves and tools, 8-h TWA exposures of up to 15.5 mg/m3 and single peak exposures of up to 85 mg/m3) were observed. NMP and its metabolites were detected in two pre-shift urine specimens. NMP and 5-HNMP concentrations in post-shift urine samples of five workers and three on-site study examiners were below 125 microg/g creatinine and 15 mg/g creatinine, respectively, while two vessel-cleaning workers showed significantly higher urinary NMP concentrations of 472 and 711 microg/g creatinine and 5-HNMP concentrations of 33.5 and 124 mg/g creatinine. 2-HMSI was detectable in four post-shift samples (range: 1.6-14.7 mg/g creatinine). The vessel cleaner with the highest NMP exposure reported irritation of the eyes, the upper respiratory tract and headaches.

CONCLUSIONS: The results of this study indicate a relatively low overall exposure to NMP in the facility. An increased uptake of NMP occurred only during extensive manual vessel cleaning. Health complaints associated with NMP exposure were recorded in one case and might be related to an excessive dermal exposure due to infrequent and inadequate use of personal protective equipment.

Abstract  This OECD Emission Scenario Document (ESD) is intended to provide information on the sources, use patterns, and potential release pathways of non-volatile chemicals used in textile dyes. The document focuses primarily on the application of dyes to fibers, yarns and fabrics by batch or continuous processes. The document presents standard approaches for estimating the environmental releases of and occupational exposures to non-volatile chemicals used in dye formulations.