Document 93X8jBjdKo9dvMBQggwJDVrYR

A Unfortunately, a knowledge of merits for contact periods of 1, 2, 4, as did toe employes' unions, and surface temperature is in itself not or 8 seconds. The measuring time is many of the 23 U.S. VCM/PVC sufficient to predict die relative safe started automatically upon thermal manufacturers, who employ some ty or hazard of human contact with contact, and "frozen" at the interval 6,500 persons at 37 plants. a heated surface. It is well known, end. Much of the resulting debate cen for example, that a metal surface is Although no installment maker, as tered around the limits set for safety. more likely to cause bums through yet, manufactures die thermesthesi- The previous level had been 500 its heat flow than a plastic surface, ometer, NBS officials report, a mar ppm vinyl chloride in the atmos though both are of the same elevated ket potential exists for it. This mar phere. Union officials urged an im temperature. ket should develop quickly if the mediate 95% emergency reduction Therefore there has beoi a need unit is used by the Consumer Prod- to 50 ppm. Several firms, however, for a definitive instrument to mea uctaVSa*ty>"^Sfiinussion as a basis argued that more time should be sure and indicate the temperature safety criteria and regulation. O taken to investigate toe problem and that would be experienced by that controls should be set by ordi one in contact with a heated. nary (and sometimes lengthy) rule face. Louis A. Marzetta, an electro engineer with the National B keeping a sharp lookout on vinyl chloride making procedures. Nonetheless, under strong union pressure, NIOSH urged toe Labor of Standards has recently dev such a device, called a "therm South Nouwatx, Cohn.--Six months ago the New Year entered Dept, to quickly issue rules requir ing a "closed system" for VCM siometer," which consists of a drical measuring probe similar with a host of problems--most of which were expected. But one parti manufacture and processing, envi ronment monitoring around VCM/ human finger. The probe is con nected to an electronic unit that gives a digital reading of the co itact temperature in degrees C. cular problem not only was unex pected, but was deadly also. In January, officials at B.F. Good rich Chemical Co.'s Louisville, Ky. FVC plants, as well as periodic em ploye medical tests. These proposals, however, included no mention of safe exposure limits. The end of the probe, design d to be pressed against the heatec test surface, is made of silicone m her; this material is resilient, as is h man tissue; and its thermal prop rties also are close to those of huma i tis plant reported that four workers had died of an extremely rare liver cancer, angiosarcoma. All had been involved in the plant's main activity: converting vinyl chloride monomer to polyvinyl chloride--the industrial Terre Haute, Ind.--A tank car con taining the controversial chemical vinyl chloride overturned here last March 17, allowing vapors to es cape through a 15 x 31-cm open ing. The tank car, owned by the sue. A heated wire, wound aroui 1 an inner core tube keeps the pro! i as sembly at 33 C--the temperatv e of a finger, and a resistance then iometer transducer inside the core tube acts as the heat sensor. Obviously, damage to tissue a heated surface is a functiori not only of the surface temperature! but also the length of time die tissue is chemical widely used, in plastic pipes, floor tiles, phonograph re cords, and countless other products. Then, in February, the company lost two more workers, again from angiosarcoma, bringing the total to six. Previously, the nationwide occurance was thought to be less frban 30 cases a year. Thus, such regulatory agencies as the National Institute of Occupa Pennsylvania Central Railroad, was lined with lead wool and "Neo prene," and It was thought that none of the liquid escaped. Nevertheless, residents were evacuated over a 15-block area as a "precautionary" measure, reports the Smithsonain Institution Center for Short-Lived Phenomena (Cam bridge, Mass.). The residents were allowed to return to their homes the following day. q in contact with the surface. I To duplicate this time factor, the mesthesiometer contains an ad| able circuit that allows tional Safety 4 Health (NIOSH) and the Occupational Safety & Health Administration (OSHA) quickly rushed into the picture. To their credit, B. F. Goodrich voluntarily limited their safe level to less than 50 ppm, as did several other manufacturers. (As of this POINTING OUT A NE\ fAT TO IMPROVE UtN SAFETY finger-like temperature it ument puts blame on faulty designs writing, laboratory mice and rats have developed angiosarcoma from breathing VCM vapors in varying amounts from 200 to 2,500 ppm, but not yet at 50 ppm. Dr. Cesare Maltoni of the Instituto Di Oncolo- gifl, Bologna, Italy, is concentrating now on that 50-ppm level in MCA- sponsored tests.) Not all firms were as concerned as B. F. Goodrich and others, who voluntarily limited exposure levels. In a March 1974 survey of five VCM and two PVC plants in the New Orleans-Baton Rouge, La., area, OSHA judged control measures to be "inadequate," and that actual exposure to the chemicals was gen erally unknown. Finally, in mid-April, OSHA pub lished in toe Federal Register an emergency, temporary ceiling of 50 ... v RSV 0006829 j ^INDUSTRIAL RESEARCH--JURE 1174 4 ppm affecting all companies making the monomer or polymerizing it. And the permanent standard, it has been rumored, may be set as low as 1 ppm. To measure the actual concentra tion, NIOSH has reportedly urged OSHA to require usage of a gas chromatograph coupled with a sam ple-collecting tube. Industry spokes men, however, have criticized that method as being expensive and not providing real-time analysis. There are other techniques, it should be noted, that may be better suited for VCM monitoring. One of these is infrared spectroscopy. Officials at Wilks Scientific Co. CLOSE WATCH ON VINTL CHLORIDE infrared gas analyzer detects at 1 ppm here discussed with Industrial Re search how typical low-level VCM monitoring can be handled with IR techniques. Says Terry F. Sinclair, "Vinyl chloride concentrations less than 100 ppm can be analyzed easily using our 'MIRAN I' Portable Cas Analyzer. This is a single-beam spectrometer equipped with a unique variable-pathlength gas cell. The vinyl chloride absorption bands at 6.15, 0.8, 10.9, and 13.9 mii are considered in quantitative analysis, and minimum detectable concentra tions are usually found to be less than 1 ppm." The choice of bands depends upon other chemicals present, as some 20 different chemicals are com monly found in VCM use or proces sing. Thus, if the environment con tains ethylene, Freon-11, perchloroethylene, and vinylidine chloride, in addition to vinyl chloride, the 13.9 Mm band will be found free from interference. Says Sinclair, "A major strength of the IK method is that, should there be interference from extran eous chemicals (such as Freon-113, which interferes slightly at 13.9 pm), it would still be safe to do the analysis. Concentrations in excess of the ceiling limit will always give ab sorbances above the limit value, and once the contaminant is known, it is relatively easy to subtract its spec trum." Infrared gas spectroscopy is suit able, for area (atmosphere) surveys, leak detection, and general VCM compliance testing. In addition there are systems available to monitor 6, 12, 24, or more remote points, such as the M1RAN 13, which can handle samples from distances approaching 60 meters (200 ft). COSMOLOGY Life on Man lay be underground MoMurdo Station, Antarctica-- A retent discovery that 10,000-year old f^u4n bacteria ran he thawed out as^Vevived may have important implications in the search for life on Mars. This concVision is based on re search perforated by a U.S.-Japan- New Zealand aAjhing team studying the frozen continent's geologic his tory. The team members, being con cerned about the frnile antartic en vironment, routinelyVnade checks that no microorganisms from the drilling team ended up irethe rocks. Biologists in the project tcx\ samples of deep rock cores drilled \p, and added them to nutrient solutions de signed to encourage bacteria gmvth. A solution prepared with drilled from a 120-meter depth hi showed obvious signs of bacteri! life. Frank Morelli of the Jet pulsion Laboratory (Pasadena, Cal.] and the Darwin Research Instit of Dana Point, Cal., initially pected that the bacteria represented the type of contamination pro ject scientists were trying m avoid. However, checks made micro organisms around the Quilling site and laboratory showedrthe cultured bacteria from the Mrop cores were not from these sources. Morelli then ran four extra checks on the cores, each time producing the same unidentified bacteria. Then, deeper cores from the same site produced slightly different bacteria strains--also unidentified-- and cores collected by Morelli's colleague, Roy Cameron, from >ther site 96-km away produced red bacteria colonies drat actreproduced. two scientists were thus forcecVto conclude that the bacteria were rative to the cores, which are datra geologically as being be Vtween ),000 1,000,000 years old. yPlaml^^he microorgan isms had svviyra in a freeze-dried form in theVfocks all these years, and had^Knap been revived by warmth^md tHfe nutrient solution. ig the rectors that kept the ria alive fonthousands of years fger than any creatures previously entified, suggests^ Cameron, were their small size andviigh concentra tion, and the low remperature of the ice-pocked antamV rocks. Cameron and Moreli point out that their discovery haV important implications in the searclraor life on other planets, especially Mars, which in some ways resembles \ntartica lf the Viking mission, designed to land instruments on the recAplanet in 1976, fails to detect life cbi the surface, Cameron notes, sciwitists may well speculate that '`the siAface permafrost of that planet may Vole the key to ancient--and living--b} deep within it." MATERIAL! depositing a heap, superhard ating Los Anceles^K new material has been discovered that is second in hardness only to diamond--and it can be produced relatively easily and cheaply. superhard material is made of titanium carbide, formed in thin lajrers through vapor deposition. De- ribed as "easily the most startling 'material development in recent years," the new titanium carbide material promises to have a wide range of uses in cutting, grinding, id wear-resistant applications. Dr. Rointan F. Bunshah, inventor orethe material and a UCLA engi neering professor, believes that ti tanium carbide can be produced at one-mmdredth to one-thousandth the colt of various commercial grades o\synthetic diamonds. In the apiming process, titanium metal atornV are vaporized by an electric beam\n a vacuum chamber. A hydrocarbonwas is then injected into the chambek and the reaction forms titanium caibide. The newly-formed vapor is then condensed and deposited at desired rates and degrees of hardness. De- Circle 1*T on Inquiry card or dtal-for-daia (treat: 800/621-0560 RSV 0006831 INDUSTRIAL RESEARCH--JUNE 1S74