Silica is toxic to the lungs but not a recognised cause of occupational asthma. The main diseases are COPD, pneumoconiosis (silicosis) and increased risk of TB and lung cancer. Silica exposure is also increased in workers with idiopathic pulmonary fibrosis.
Foundry workers exposed to silica may develop occupational asthma from the binding agents used in moulds and cores (isocyanates from the cold box system, formaldehyde from the hot box, furanes and amines).
The Oasys Audit scheme started midway through 2010 and collects agents typed in through the Oasys program. The years before 2010 show old data entered during 2010 or later and are likely to have many fewer notifications. We expect Oasys to become more widely adopted as time goes by so increasing notifications does not necessarily mean an increasing problem.