A new review highlights new developments in understanding the health effects of silica, and calls for action to reduce illness and death from silica exposure at work, including stronger regulations, heightened awareness and prevention, and increased attention to early detection of silicosis and lung cancer using low dose CT scanning.
For centuries, silica has been known to cause lung disease (silicosis). Evidence that silica causes lung cancer has been more recent, accumulating over the last several decades. Writing in CA: A Cancer Journal for Clinicians, Kyle Steenland, PhD, at the Rollins School of Public Health at Emory University in Atlanta, and Elizabeth Ward, PhD, of the American Cancer Society highlight three important developments that hold potential to prevent illness and death from silica exposure at work.
The first development is the publication of recent studies providing detailed exposure-response data, enabling regulations based on quantitative risk assessment. New studies have also shown that silica-exposed workers who do not have silicosis and who do not smoke still have increased rates of death from lung mortality.
Second, a new rule lowering the permissible occupational exposure for the estimated 2.2 million US workers currently exposed to silica is currently under consideration. Risk assessments estimate that lowering occupational exposure limits from the current to the proposed standard will reduce silicosis and lung cancer mortality to approximately one-half of the rates predicted under the current standard.
Third, low-dose computed tomography scanning has now been proven to be an effective screening method for lung cancer. The authors recommend that clinicians ask about occupational history to determine if silica exposure has occurred, and if it has, that extra attention might be given to the early detection of silicosis and lung cancer, as well as extra emphasis on quitting smoking. The authors recommend that individuals with significant occupational exposure to silica be offered screening beginning at age 50 years if they also have smoked the equivalent of one pack a day for at least 20 pack-years; what experts call 20 pack-years of smoking.
The report says while there is some low-level silica exposure on beaches and in ambient air in general, there is no evidence such low-level exposure causes health effects. The more concerning exposures occur on the job, most often in the construction industry. Exposure occurs when workers cut, grind, crush, or drill silica-containing materials such as concrete, masonry, tile, and rock. About 320,000 workers are exposed in general industry operations such as brick, concrete, and pottery manufacturing, as well as operations using sand products, such as foundry work. Others are exposed during sandblasting. Silica exposure also occurs from hydraulic fracturing (fracking) of oil and gas wells.
The most effective measures for the control of occupational silica exposures include banning sandblasting, substituting metal grits for abrasive blasting, modifying processes and equipment, and controlling dust transmission by using enclosures, air curtains, water spray, and ventilation techniques, and the use of personal protective equipment.
“Current regulations have substantially reduced silicosis death rates in the United States, but new cases of silicosis continue to be diagnosed,” says Dr. Steenland. “And while the lung cancer risk associated with silica exposure is not as large as some other lung carcinogens, like smoking or asbestos exposure, there is strong and consistent evidence that silica exposure increases lung cancer risk.”
Article: Silica: A Lung Carcinogen, Kyle Steenland, PhD; Elizabeth Ward, PhD, CA Cancer J Clin 2013
David Sampson | EurekAlert!
Team discovers how bacteria exploit a chink in the body's armor
20.01.2017 | University of Illinois at Urbana-Champaign
Rabies viruses reveal wiring in transparent brains
19.01.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences