Lime and sand
Lime is a natural product mostly consisting of calcium oxide. It is very alkaline and takes up CO2 from the atmosphere converting to calcium carbonate. Lime often also contains magnesium oxide, silicon oxide and smaller amounts of aluminium oxide and iron oxide. It is a constituent of building cement, the main exposures occur during mixing mortar and probably during demolition of concrete buildings. Acute high exposures are probably a cause of acute irritant induced asthma, and may have accounted for some of the problems following the collapse of the world trade centre in New York. We believe that low dose regular exposure can cause occupational asthma with latency (low dose irritant induced asthma) with daily deterioration with usual-level exposure. We have one worker with a positive immediate asthmatic reaction during specific challenge to lime dust with an increase in methacholine reactivity and an increase in FeNO after exposure. It may also be responsible for work-agravated asthma when asthmatics are exposed to construction dust at work.
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.