Engineering Controls Program

In June 2016, the Occupational Safety and Health Administration put a new rule into effect on occupational exposure to respirable crystalline silica. NIOSH researchers provided testimony at public hearings in March 2014 when the rule was first proposed, addressing the health effects of exposure to respirable crystalline silica based on its long history of research and extensive efforts to develop recommendations and controls for preventing worker exposures to silica. NIOSH researchers have studied the use of engineering control technology for grinding concrete, sandblasting, rock drilling, hydraulic fracturing (fracking), concrete floor polishing, cutting fiber cement siding, tuck pointing, and asphalt milling. In fact, NIOSH construction researchers played a significant role in helping to develop Table 1 of OSHA’s rule concerning “Exposure Control Methods for Selected Construction Operations.” NIOSH has also promoted the prevention of silicosis through model partnerships and cooperative agreements with government, industry, labor and academia. NIOSH methods research has shown that the proposed OSHA standard is measurable by techniques that are valid, reproducible, attainable with existing technologies, and available to industry and government agencies. Learn more at the NIOSH Topic Page on Silica.

Learn about workplace solutions for controlling exposures to Respirable Crystalline Silica in construction and hydraulic fracturing. Go to: https://www.cdc.gov/features/preventing-silicosis/index.html

NIOSH researchers developed and tested a technology called the “mini-baghouse” that can protect oil and gas extraction workers by effectively controlling silica dust emitted from sand movers at hydraulic fracturing worksites. NIOSH has been working with industry partners to help advance this novel, potentially life-saving technology and bring it to market through commercial licensing. Now called The NIOSH Mini-baghouse Retrofit Assembly, this innovation is patent-pending, designed and engineered as a “bolt on” aftermarket retrofit for the many sand movers currently operating at hydraulic fracturing sites in the United States and internationally. Next, NIOSH plans to enhance the performance of The NIOSH Mini-baghouse Retrofit Assembly with several engineering improvements to the clamping mechanism, weather resistance and sealing surface prior to commercial transfer.

Learn more:

• Q&A with the lead engineer
• Short description of the Mini-Baghouse Retrofit Assembly
• Reports from the first and second field evaluations

From 2003 to 2016, NIOSH engineers worked collaboratively with a National Silica/Asphalt Milling Machine Partnership to test engineering controls designed to reduce respirable crystalline silica exposure during asphalt pavement milling in highway construction. As a result of the collaborative research, NIOSH published a Best Practices document (NIOSH Publication No. 2015-105) that was a keystone achievement of the multi-year efforts, leading research and working with labor, industry, and government stakeholders to reach a voluntary agreement that places silica dust controls (proven to control silica hazards to levels below occupational exposure limits) on all new milling machines sold in the U.S. by January 1, 2017. Two manufacturers, representing 80% of the U.S. market, were so accepting and committed to the NIOSH-published best practices that they began installing silica dust controls in 2014, three years ahead of the deadline. The engineering control solution is a ventilation system integrated into the milling machine that captures and removes dust generated in the cutter drum housing of the machine before it can contaminate the working environments of the milling machine operator and ground workers.

Learn More

• NIOSH Science Blog about the Silica/Asphalt Miling Machine Partnership
• Short description of the Silica/Asphalt Miling Machine Partnership
• Field Guide for Controlling Silica Dust Exposure on Asphalt Pavement Milling Machines

Attaching a regular shop vacuum to a dust-collecting circular saw can provide a simple, low cost solution to reduce exposure to hazardous dust produced when construction workers cut fiber-cement siding. NIOSH published this recommendation in Workplace Solutions Workplace Solutions: Reducing Hazardous Dust Exposure when Cutting Fiber-Cement Siding.

Learn more:

• Short description of the study and the Workplace Solutions document
• Report from a field study

By 2020, the National Science Foundation estimates that nanotechnology will have a $3 trillion impact on the global economy and employ 6 million workers in the manufacture of nanomaterial-based products, of which 2 million may be employed in the United States. As new manufacturing technologies are developed, novel materials with unknown toxicological properties will require proper risk management approaches. In 2013, NIOSH researchers published the document, Current Strategies for Engineering Controls in Nanomaterial Production and Downstream Handling Processes, that provides engineering control approaches for mitigating exposures for nanomaterial producers and downstream users. This document was the first to provide specific approaches to controlling exposures in many common unit processes that have been shown to result in occupational exposures. The document has been widely distributed through a variety of channels including web dissemination, contact with stakeholders, and multiple presentations with key partners (AIHA, universities, government laboratories). Since its release, the document has been downloaded almost 6,000 times. NIOSH intends to publish short information sheets with visuals and schematics to better communicate recommended engineering control approaches.

Learn more:

• NIOSH Topic Page on nanotechology
• NIOSH Update on new research-based recommendations to control worker exposures to nanomaterials
• NIOSH Science Blog on controlling exposures to workers who make or use nanomaterials
• Presentation on Engineering Controls for Nanotechnology

Occupational exposures to diacetyl in the microwave popcorn and flavoring industries have been associated with severe respiratory disease, such as obliterative bronchiolitis. The Flavor and Extract Manufacturing Association reports that of the more than 1,000 flavoring ingredients considered to be potential respiratory irritants or hazards, only 46 have established OSHA permissible exposure limits (PELs). Given the lack of occupational exposure limits for most flavoring ingredients, assessing workplace exposures and developing exposure control guidance are critical to help reduce the risk of flavorings-related lung disease. NIOSH researchers released a document of best practices which provides recommendations for controlling exposure to diacetyl and 2,3-pentanedione during common production processes. It contains 12 pages of engineering control schematics, including new NIOSH designs that manufacturers can quickly adopt to reduce inhalational exposure. These approaches have been validated in the laboratory and in flavoring manufacturing facilities and have shown reductions in exposure potential between 75-99% during the most common production tasks (small scale weigh-out, large tank mixing, product packaging etc.).

Learn more:

• Criteria for a Recommended Standard: Occupational Exposure to Diacetyl and 2,3-Pentanedione
• NIOSH Update that provides a summary of the Criteria document

From 1990-2008, over 800 boating-related carbon monoxide (CO) poisonings were identified based on hospital records, press accounts, and other sources. NIOSH investigations on houseboats showed that uncontrolled generator exhaust emitted near the rear deck resulted in extremely hazardous CO concentrations in that area and near the water. NIOSH researchers worked with boat and marine engine manufacturers, along with the U.S. Coast Guard, to encourage the use of simple exhaust configuration changes and the adoption of generator emission controls to reduce the potential for carbon monoxide poisonings on houseboats. This effort culminated in the development of catalyst-based low CO emission generators by the two largest manufacturers of marine power generation systems, Westerbeke and Kohler. The United States Environmental Protection Agency , relying heavily on NIOSH engineering control research, adopted a low CO emission standard for all marine generators. CO emission standards were also promulgated by the EPA for several other marine engines including sterndrive/inboard, personal water craft and outboard engines. As of 2015, the National Park Service is also requiring that all concessionaires renting boats in national parks implement exhaust stacks or emissions controls on houseboat generators in accordance with NIOSH recommendations. These new rules have provided significant reductions in CO emissions, and a much safer environment for boaters. Learn more at the NIOSH Topic Page on carbon monoxide dangers in boating.

Beginning in 2014, NIOSH launched information, tools, and resources through the Buy Quiet initiative to encourage manufacturers to design quieter equipment, and encourage companies to purchase or rent quieter machinery. Buying quiet is a noise control strategy for workplaces and the community. As part of this initiative, NIOSH developed the Buy Quiet website and the Database of Noise Levels for Machinery and Power Tools with the goal of reducing noise-induced hearing loss among the nation’s workers by providing information and tools to facilitate the implementation of Buy Quiet programs.