Clinical appearance, radiologic findings, lung function and results of corticosteroid therapy were analyzed in 42 adult cases of biopsy-proven pulmonary histiocytosis X. Symptoms were present in only 64%. Using the ILO classification 1980, the evaluation of chest radiographs revealed all categories of profusion, size and shape of nodules. The characteristic ‘ring figures’, i.e. thin-walled cysts, in the parenchyma were detected in 78% of conventional tomographies (n = 27) and in all patients examined by CT (n = 5). In patients with early disease, lung function tests (n = 26) including body plethysmography, pulmonary diffusing capacity and ergospirometry revealed that parameters of gas exchange are most sensitive (T_{L, co} 84%, K_co 72%). Bronchial reactivity to carbachol was significantly higher than in controls (n = 12). Lung perfusion scintigram showed an abnormal, but uncharacteristic pattern in 81% (n = 26). During corticosteroid therapy, no progression was observed (n = 36). 85% of patients with radiographic evidence of progressive disease improved after administration of corticosteroids (n = 14).

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Two recent, tragic events remind us that the broad topic of high-energy release events encompasses more than vapor cloud explosions and reactive chemical incidents. Dust explosions also have potential for causing catastrophic harm to personnel and facilities. This paper describes recent, major dust explosions with a particular focus on learnings related to a commonly underconsidered aspect of facility operations-housekeeping.

The American Institute of Chemical Engineers (AIChE) Center for Chemical Process Safety (CCPS) has developed a guideline describing a new riskbased approach that an organization can use in defining and implementing a process safety management system specific to its unique needs. Recognizing the importance of safety culture as a determinant of safety performance, CCPS has included process safety culture as one element in the new risk-based process safety (RBPS) model. This paper will describe both the new process safety culture element and its integration in the overall RBPS model.