NIOSH

This week the Occupational Safety and Health Administration (OSHA) fined a carbon steel foundry in Wisconsin $95,480 for willfully overexposing their workers to crystalline silica, a known carcinogen. Ironically, this news comes shortly after a group of citizens petitioned the Wisconsin Department of Natural Resources (DNS) to adopt more stringent rules governing emissions of respirable crystalline silica.

Crystalline silica is a particularly dangerous air pollutant because it is a basic component of soil, sand, brick, granite and other common materials. As a byproduct of many everyday industrial processes like mining, construction, and glass manufacturing, it is a ubiquitous presence for some workers. Industrial processes that involve abrasive blasting or the use of sand and quartz are also sources of crystalline silica exposure, which is why many of these workers are concerned over the increasing popularity of fracking in their state. The hydraulic fracturing (AKA “Fracking”) process involves fracturing rock layers with a fluid that includes sand or ceramic material in order to extract the gas underneath. As you can tell from the description, stirring up compressed rock dust and sand particles is a definite health concern, so it’s good to see those at risk aware of it and addressing the matter.

The petitioners are asking the Wisconsin DNS to classify respirable crystalline silica as a hazardous air pollutant under their air toxics rule. Furthermore, the petitioners recommend that the DNS comply with the standard set by the State of California Office of Environmental Health Hazard Assessment which dictates a limit of 3 micrograms per cubic meter and requires consistent monitoring and enforcement.

Determining the concentration of crystalline silica and amorphous silica by the National Institute for Occupational Safety and Health (NIOSH) standards requires capturing particulates from an air sample on a 0.45 micron, 25 mm diameter Silver Membrane Filter and then analyzing the particulate matter for silica using X-Ray diffraction (XRD). See NIOSH methods 7500 and 7501 for the complete procedure.

Read the full petition by Wisconsin citizens here.
Also see this report on silica from the Wisconsin DNS.

Coal miners could be at greater risk to lung ailments caused by air-borne contaminants such as crystalline silica, according to a new NIOSH (National Institute for Occupational Safety and Health) publication. After reviewing information that had been published over the last 15 years the agency determined that miners may face increased exposure to these harmful materials as the more productive seams of coal are mined out, forcing them to dig deeper into thinner mining seams. The result is longer working hours in environments that have denser concentrations of crystalline silica, creating respiratory and pulmonary disease.

NIOSH is responsible for setting guidelines on exposure levels of damaging substances like crystalline silica as well as recommending the sampling procedures for these toxic particles. The NIOSH sample technique for crystalline silica involves redepositing the sample onto a 0.45 micron, 25 mm silver membrane filter for analysis by x-ray diffraction. Testing for air-borne contaminants is one of the most common applications for our silver membranes. NIOSH did not make any changes to the sampling method in their new report. In fact, these new findings strengthen their concerns about the respiratory health effects caused by coal mine dust.

A new study by NIOSH found a more effective method for testing occupational exposure to airborne wood dust, which is known to cause cancer. This new practice incorporates silver membrane filters along with a mid-infrared diffuse reflection method for direct on-filter determination of wood dust mass instead of gravimetric analysis and glass fiber filters, creating a more specific test.

To learn more, you can view the article abstract here.