The mortality from 1946 to 1975 of over 900 North Italian chrysotile asbestos workers first employed between 1930 and 1965 has been studied. Nine deaths were certified as attributable to asbestosis, and eleven to lung cancer. One death was attributed to mesothelioma of pleura but this diagnosis was not supported by histological examination. Comparison with the national figures for all Italy did not reveal an excess of deaths from lung cancer but during the last quinquennium of observation, the SMR for lung cancer rose to 206. Simulation experiments enabled a dust index in fibre/years to be attached to each man in the cohort. All but two of the deaths from lung cancer occurred in the higher exposure group. The relative risk of lung cancer in this group was 2.89. The eleven workers who died from lung cancer were all cigarette smokers. A further period of observation is required to monitor the mortality of the surviving workers.

The Department of Energy (DOE) and the DOE Natural Phenomena Hazards Panel have developed uniform design and evaluation guidelines for protection against natural phenomena hazards at DOE sites throughout the United States (UCRL-15910). The goal of the guidelines is to assure that DOE facilities car_withstand the effects of natural phenomena such as earthquakes, extreme winds, tornadoes, and flooding. The guidelines apply to both new facilities (design) and existing facilities (evaluation, modification, and upgrading). The intended audience isprimarily the civil/structural or mechanical engineers conducting the design or evaluation of DOE facilities. DOE Order 6430. lA, General Design Criteria Manual, was revised in 1989. This current version of Order 6430. lA references these guidelines (UCRL-15910) as an acceptable approach for design evaluation of DOE facilities for the effects of natural phenomena hazards. UCRL-15910 provides earthquake ground acceleration, wind speed, tornado wind speed and other effects, and flood level corresponding to the design basis earthquake (DBE), design basis wind (DBW), design basis tornado (DBT), and design basis flood (DBFL) as described in Order 6430.1A. Integrated with these natural phenomena Ioadings, UCRL-15910 provides recommended response evaluation methods and acceptance criteria in order to achieve acceptably low probabilities of facility damage due to natural phenomena. iv recent information and techniques available, In any case, to achieve a specified perforrnance goal, hazard annual probabilities of exceedance are specified with design and evaluation procedures that provide a consistent and appropriate level of conservatism.

The paper describes experimental and computational studies of weakly ionized air plasmas sustained by high repetition rate high-voltage nanosecond pulses. The experimentally determined energy cost per newly produced electron in these diffuse volumetric plasmas is on the order of 100eV, two orders of magnitude lower than in diffuse quasineutral dc and rf plasmas, and close to that in the cathode sheaths of glow discharges. Modeling of plasma dynamics in high-voltage nanosecond pulses yielded the energy cost of ionization in good agreement with the experimental values. Both experiments and modeling revealed that the ionization cost per electron in these plasmas is relatively insensitive to the gas density. Detailed investigations of the plasma dynamics revealed a critical role of the thin cathode sheath that was found to take up most of the peak voltage applied to the electrodes. The extremely high values of the ratio of electric field strength to the gas number density (E∕N), much higher than the Stoletov’s field at the Paschen minimum point, result in a very high ionization cost in the sheath. In contrast, the value of E∕N in the quasineutral plasma is closer to that associated with the Stoletov’s point, resulting in a near-optimal electron generation. This behavior (the reversal of ionization efficiencies in the sheath and in the plasma) is opposite to that in conventional glow discharges. The positive space charge in the sheath and its relatively slow relaxation due to the low ion mobility was also found to result in reversal of electric field direction in the plasma at the tail of the high-voltage pulse.

The emotionalised subject of asbestos is treated in chronological terms: how the "magic mineral" known in ancient times in Europe and Asia became in the late nineteenth century an important industrial resource of particular interest to the navies of the world; and how its malign effects gradually became apparent during the presgnt century. The media have made asbestos a notorious villain, but it still has properties and applications useful to society if they are properly controlled in the same way as other industrial hazards. One important application is the manufacture of asbestos cement pipes which are a convenient and cheap method of providing water supplies and sewage disposal for developing countries. An appeal is made for prudence and not hysteria in relation to the use of mineral fibres of all types.No subject has raised more emotion in the field of occupational health in the past 25 years than asbestos. This is a pity since scientific issues should not become emotional. Unfortunately, the fault lies with ourselves, at least with some of us who ought to know better than to provide the sensation seeking media with ammunition for their misconceived campaigns and the legal profession and the asbestos removal contractors with a rich harvest.

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