Occupational Protection

Safety at the workplace: what to consider when using Neuburg Siliceous Earth ?

When handling or working with Sillitin, Sillikolloid, Aktisil and Silfit, Aktifit fillers, their fine particle size can give rise to an undesirable generation of lung-penetrating (fibrogenic) dusts. This possibility has, therefore, to be taken into appropriate account when establishing a work-hygienic ‚Risk Assessment’.

Phase analytical studies of Neuburg Siliceous Earth have shown the presence of crypto-crystalline silica. For this portion – if present in the form of dust – a fibrogenous (or fibrotic) action cannot be excluded, which means that inhalation of high amounts of such dust over long periods of time potentially can lead to silicosis. It is consequently advisable to monitor the dust exposure and comply with existing limits.

This quartz-like risk potential, as well as the discussion started in 1997 by IARC with the new classification of quartz, has also lead to in-depth studies with respect to toxicological effects of Neuburg Siliceaous Earth, whose silica content until very recently was thought to be composed of quartz. Several in vitro investigations at IBE (Bruch et al., 2001-2007) with cross-validation by in vivo experiments, upon analysis of the vector model have confirmed a markedly different toxicological profile for Neuburg Siliceous Earth, in the direction of a considerably lower toxicity level as compared with other quartz-containing products.

We would like to draw your attention at this point to a qualifying statement found in 1997 IARC Monographs, which puts the classification of quartz as carcinogenic to humans (Group I) into perspective in a most interesting way:

“As part of their overall assessment, the IARC working group noted that a carcinogenic effect was not found in all the industrial situations examined. A carcinogenic effect may depend on the properties inherent to crystalline silica or on external factors, which influence the biological activity or the distribution of silica polymorphs.”

A cohort study conducted by the German 'Institut für Prävention und Arbeitsmedizin' (KAFKA Studie 2011) at the sites of Hoffmann Mineral substantiated these particular circumstances. It encompasses 675 empolyees who worked for Hoffmann Mineral during the time period of 1923 till 2007.

The epidemiological findings of more than 80 years handling Neuburg Siliceous Earth could be summarized in the following conclusions:

Lung cancer:
Though a large number of empolyees were exposed to a highly elevated concentration (cumulative concentrations up to 90 mg/,³ x year) of crypto-crystalline silica dust the study could not identify any significant lung cancer risk.

Silicosis:
Employees who worked underground or worked under long lasting exposure conditions of > 0,15 mg/m³ alveolar respirable dust (crypto-crystalline silica) were at higher risk to get silicosis.