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CALCIUM CHLORIDE WHITE

This Early Sign of Failure is a Threat to Driving Safety, Public Health and the Environment

By Gerry Matthews Retired - Senior Account Executive Occidental Chemical Corporation (OxyChem)

Dust produced by traffic on unpaved the overall cost of road maintenance aggregate in a road surface leaves the is an unpleasant nuisance, while providing taxpayers with safer, larger material unstable and vulnerable— affecting the quality of life for everyone more drivable roads, as well as a cleaner subject to degradation and loss with who travels on gravel roads and those and healthier environment. Simply put, every passing , or washout in a who live or work nearby. It is also a everyone benefits when communities hard rain. When gravel roads deteriorate, warning sign of costly road damage that invest in an effective dust control program ruts, potholes, and washboards form, can increase maintenance requirements for their roads. increasing the need for spot repairs and and strain road commission budgets. overall blading with grading equipment. Most unpaved roads are located miles Just as important, road dust can threaten Over time, the deterioration associated from the networks of paved highways driving safety and public health, damage with dust can become so severe, the road serving major metropolitan areas. Yet, and other property, and harm our gravel must be replaced or supplemented these rural roads are an essential link in . with additional material. the transportation infrastructure. They Considering that there are more than provide millions of people with vital Higher Maintenance Expense two million miles of unpaved roads in access to work, schools, grocery stores, Budgets for road maintenance and the U.S. and more than 600,000 km and health care facilities. They also link improvement are under constant in Canada,1 efforts to control road dust farms, forests, mines, and wells—as well pressure, yet motorists, residents, and are national and international in scope. as manufacturers and product distributors— businesses demand quality roads that But maintenance responsibility for with far flung markets, protecting jobs are safe and comfortable to drive on. unpaved public roads most often rests and bolstering the economy. Premature deterioration of unpaved with local officials, who must balance Unpaved roads are too important to roads increases the need for blading and resources spent battling dust control neglect. Dust control is a valuable other maintenance to keep roads in safe with other pressing needs. Fortunately, preventative maintenance measure that and drivable condition. More frequent local road authorities have access to protects the durability of those roads maintenance places an added burden on proven dust suppressant products and for better long-term performance, as work crews and increases equipment and application methods that have been well as significant cost-savings. Let’s labor expense. That can lead to cutbacks used successfully for more than 100 review the important reasons why dust in other areas of the budget. years to achieve effective, long-term, control should be considered by those and economical dust control when Unsafe Driving Conditions responsible for maintaining unpaved incorporated in normal seasonal road roads in most regions of North America. According to the Insurance Institute maintenance programs. for Highway Safety-Highway Loss Data Washboards, Potholes, and Ruts Why Control Dust? Institute, 63% of passenger vehicle Road experts will tell you, a dusty road is occupant deaths occur in rural areas. When the importance of dust control a deteriorating road. Dust is comprised of Although there are many reasons for rural is weighed against all other budget fine which, when they separate traffic fatalities, reduced due to priorities, it is important to remember that from coarse aggregate, no longer serve road dust on unpaved roads can be a investments in suppressing road dust are as the binding agents necessary to hold contributing factor in many accidents. repaid in significant direct and indirect road surfaces together. Separation of In addition, a loose dusty surface can benefits. Dust control can help reduce fine material from coarse load-bearing reduce vehicle traction, increasing

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stopping distances. When loose gravel Environmental Protection Agency (EPA) they serve. Effective dust control is thrown into the air by spinning , PM10 primary (public health) and preserves the drivability and durability coarse components become projectiles secondary (public welfare) air quality of unpaved roads, while minimizing that can endanger motorists and standards that call for concentrations impact on the natural environment, and pedestrians. not to exceed 150 micrograms per cubic protecting health, safety, property, and meter of air. The 2006 PM10 standards quality of life. Damage to Vehicles remain in effect after PM2.5 standards U.S. auto glass repair shops generate for fine were revised in 2 4 more than $1 billion in annual revenue. December 2012. Effective dust control can If just a portion of that amount is for Impact on the Environment repairing vehicle damage caused by loose reduce the overall cost to aggregate on gravel roads, the economic The effect of road dust on natural scenery maintain unpaved roads impact of poor unpaved road conditions and fresh air is unmistakable. But dust by 30% or more. is very steep. Loose aggregate not only is also a harmful in ways that damages windshields, this airborne are less obvious. Dust from roadways filth also takes its toll on paint, chrome, and from road maintenance operations The benefits of dust control on road headlights, suspension systems, and can drift or wash into streams and maintenance costs are significant and other components. Dust clogs filters, other waterways, increasing sediment measurable. Effective dust control can erodes seals, and forms an abrasive and possibly harming aquatic plants reduce the overall cost to maintain grit between moving parts. The harsh and animals. Airborne dust also coats unpaved roads by 30% or more. vibration caused by washboards and crops and vegetation near unpaved Field trial results have shown that the impact of potholes harms steering roads, stunting their growth.5 According when calcium chloride, a leading dust systems, tires and rims, while loosening to Iowa State University researchers, suppressant, is used to control dust on other components and contributing to one car traveling an untreated gravel gravel roads, blading frequency may be long-term vehicle wear and tear. road once per day throws off one ton of decreased by up to 50% and aggregate gravel per mile (560 kg/km) per year. In Hazard to Health life can double.6 Field trials outside of the many jurisdictions regulations require U.S. revealed that the anticipated interval Dust is an airborne pollutant that can that property owners control release of between re-graveling was extended from degrade regional air quality and pose a “fugitive” dust generated by mining, 7 to 14 years when roads were treated hazard to public health. According to transportation, and other industrial and with calcium chloride. a 1992 study cited by researchers at commercial operations to prevent its Colorado State University, nearly escape into the surrounding environment. While not as easily measurable in 34% of the particulate in the dollars and cents, the safety, health, Lower Quality of Life above the U.S. originates environmental, and quality of life benefits from unpaved roads.3 People exposed to It is difficult to put a price tag on the of dust control help support other airborne dust can experience respiratory pleasure of playing in the yard, walking or societal goals: Healthcare costs can be symptoms including irritation, coughing, bicycling along a country road, hunting reduced, auto insurance rates can come or difficulty breathing. Exposure to dust or fishing, bird watching, or just basking down, and tax increases to fund road particles in the air can also decrease in the . But all of those experiences repairs can be avoided. Dust control can lung function and aggravate or can be diminished by choking clouds of also help businesses comply with EPA hay fever. Dust can convey diseases like road dust. Dust also reduces leisure time air quality regulations or state fugitive tetanus that are harbored by . Some by increasing the need to clean windows dust requirements. The need for gravel health experts even believe that chronic and siding, and sweep sidewalks and mining and related transportation can and irregular heartbeat can porches. It can increase energy bills and be reduced, and related environmental result from exposure to , reduce discretionary income by forcing impact can be minimized when dust and premature death is possible if homeowners to machine dry laundry and control makes roads more durable. individuals already suffer from lung or use air conditioning to cool their homes. heart disease. Calcium Chloride: A Proven Answer Tangible Benefits of Dust Control Compliance with EPA Regulations For more than a century, calcium chloride Considering the problems road dust has compiled a proven record of effective Road dust is considered a coarse creates, identifying and implementing dust control across North America under particulate, 10 microns or smaller in effective solutions should be a high a wide range of gravel and size, and subject to the 2006 U.S. priority for road officials and the taxpayers conditions. Calcium chloride (or CaCl2)

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is a hygroscopic salt that draws moisture applications. DOWFLAKE™ Xtra contains concerns regarding brine content, some from the air to form a solution in road 10% more active ingredient (CaCl2) jurisdictions have enacted regulations gravel that keeps road surfaces constantly than competing calcium chloride flake requiring permits for the use of well head damp—and dust at bay—even in hot, dry products. The higher concentration of brines to treat roadways.7 conditions where other materials fall short. the product increases the area of dust Use of brines to achieve the same level control coverage, reducing overall This moisture helps to bind fine and of dust control as calcium chloride would application costs. coarse aggregate particles together increase the cost of an effective dust to create a longer-lasting, hard, and Avoid Well Head Brines control program. In one comparison, 0.46 compact road surface. Because moisture gal/yd2 of well head brine was required to penetrates several inches into the Calcium chloride products supplied by achieve the same hygroscopic capacity as road base, the damp gravel conditions OxyChem suppress dust more effectively 0.28 gal/yd2 of LIQUIDOW™ 38% calcium cultivated by calcium chloride also than the inexpensive well head brines— chloride. A 3,700 gallon truck making contribute to overall road surface stability. also known as weak, natural, well, three trips per day could treat 3.4 miles Calcium chloride depresses the freezing or oil field brines—that are sometimes per day with LIQUIDOW™ 38% calcium point of the moisture in the road surface applied to road surfaces. Most well chloride and only about 2.1 miles per day to help minimize frost heave damage in head brines typically contain very small with well head brine. The resulting higher the winter, further reducing maintenance concentrations of calcium chloride and/ transportation and application costs can requirements. While the first application or magnesium chloride (MgCl2), which quickly offset any per-gallon cost savings of calcium chloride on a gravel road is another hygroscopic salt. Well head on the material itself. provides immediate dust suppression, brines also contain significantly higher subsequent seasonal applications on levels of sodium chloride (NaCl), which Dust Control Best Practices the same roadway have a cumulative does not have the moisture attraction Dust-free roads are built on a foundation effect. Each new application builds on properties of CaCl or MgCl . Sodium 2 2 of quality gravel. The proper mixture of fine residual dust suppressant remaining from chloride actually remains solid under material and larger aggregate is important previous treatments, which can enable most summer climate conditions instead to ensure that natural binding action application rates to be reduced and/or of attracting moisture and forming a is maximized. For best performance, road quality to be improved. solution that dampens road surfaces to aggregate should meet these criteria: control dust. The lower hygroscopic salt content in ...three times more Recommended Aggregate Characteristics well head brines is clearly evident when Characteristic Preferred Acceptable well head brine would compared side-by-side in the field with Maximum ¾ Inch 1 Inch have to be applied the dust control performance of calcium Size to achieve the same chloride. In one study on a ¾-mile section Grading Well Graded—Not Uniform or hygroscopic performance of gravel road, LIQUIDOW™ 38% calcium Description Skip Graded as LIQUIDOW™. chloride was compared to a well head Percent Pass 55 to 70 50 to 75 brine containing 15% NaCl and only a #4 total of 12% CaCl and MgCl combined. Percent Pass 14 to 17 12 to 17 2 2 #200 Controlled sampling over seven weeks Both liquid and solid forms of calcium (Nonplastic) found that LIQUIDOW™—with more than chloride are hygroscopic and may be Percent Pass 12 to 15 8 to 15 three times as much hygroscopic salt— #200 (Plastic) used to increase moisture content in road controlled dust three times better than surfaces to effectively control dust. Solid Plasticity 2 to 9 Nonplastic the well head brine. Index CaCl may be applied directly to the road 2 Los Angeles Less than 30 Less than 40 surface or dissolved in water for liquid In this example, three times more well Abrasion head brine would have to be applied application. OxyChem supplies both Percent Greater than Greater than types of calcium chloride: LIQUIDOW™ to achieve the same hygroscopic Fracture, 85% 75% Technical Grade Calcium Chloride performance as LIQUIDOW™. Application One Face Solution is available in concentrations of that much brine could have harmful from 28 to 42%. Anhydrous Calcium environmental effects, increasing the Chloride 94-97% Mini Pellets and potential for run-off or other impact. A season-long dust control program DOWFLAKE™ Xtra 83-87% Calcium Relatively high levels of sodium chloride begins in the spring. The road should be Chloride Flakes are the recommended can be detrimental to soil structure bladed while the moisture content and solid products for dust control and permeability. In light of these humidity are relatively high.

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Unless rain has fallen within the previous with appropriate handling and residents, visitors, communities, and two days, the road surface should be application procedures. businesses. Dust control incorporating watered prior to blading. Blading will calcium chloride provides significant Calcium and chloride are considered remove ruts, washboards, and potholes, benefits to all of society, keeping unpaved essential constituents in the bodies of all and help mix-in loose aggregate. Good roads more drivable and safe, protecting animals and the human acute oral toxicity drainage is essential. Shaping roads to public health and the environment, of calcium chloride is classified as low. In a 4% or greater crown will help ensure and removing an unpleasant nuisance normal dust control use, calcium chloride proper drainage. While the road surface is from everyday life. Dust control using does not pose a significant risk to the being prepared, ditches, shoulders, calcium chloride can also contribute to environment. The likelihood of damage and culverts should be reshaped and road maintenance savings, preserving to vegetation can be significantly limited cleaned as needed. precious budgetary resources and if dust control applications follow current providing welcome relief for taxpayers. When blading and shaping are completed, recommended and standard practices. With more than 100 years of safe and dry or liquid calcium chloride is applied. It Ground and surface waters are not likely effective use, calcium chloride is a proven is usually preferable to water the surface to be affected by calcium chloride dust remedy for dust and the problems it prior to spreading a solid product. Roads suppressant applied in accordance with causes, outperforming well head brines may be slippery while solid product remains recommended practices, because the and sparing communities the potential on the surface. If roads will remain open product tends to remain bound in the environmental impact associated with to traffic, signs should be posted directing road surface for extended periods of their use. motorists to use appropriate caution. time, and any material washed into the To learn more about the benefits of dust Calcium chloride application rates environment is typically well diluted. control and why calcium chloride plays required to achieve effective dust control For this reason, levels of chlorides an important role in controlling dust may vary depending on local conditions released into surface or ground water effectively, visit StableRoads.com. and past experience. When in doubt, under properly administered road dust an authorized LIQUIDOW™ distributor treatment programs should not pose a can offer a recommendation. OxyChem significant threat to pets and wildlife. offers assistance in identifying qualified Using calcium chloride However, proper application of calcium distributors with the proper expertise at for dust control makes chloride includes measures to avoid StableRoads.com/Distributors. contamination of surface or ground water roads more durable, In the weeks and months after initial because excessive amounts of chloride reducing blading application, road crews can maintain salts can be harmful to aquatic life. The requirements and helping optimum dust control during unusually calcium component of the material is not maintain water quality. long periods of hot, dry weather by a concern because it is a component of watering the road surface to reconstitute nearly all natural waters and is classified the treatment. Re-application of calcium as practically non-toxic to aquatic chloride as needed in the late summer organisms by the U.S. Environmental or early fall will further prolong dust Protection Agency (EPA).8 suppression. Application of calcium The United States Department of chloride is not recommended during Agriculture (USDA) Forest Service heavy rainfall, or if rain is threatening, identified blading as a contributing because rain may leach out or dilute factor in runoff of harmful sediment from the chloride and may cause it to run off roads into roadside streams and other of the road. waterways. Using calcium chloride for Managing Impact dust control makes roads more durable, reducing blading requirements and Anytime a substance is used in proximity helping maintain water quality. to people or natural areas, there is an understandable concern about possible A Valued Investment health or environmental effects. In Clouds of road dust signal the the case of calcium chloride used in deterioration of valuable infrastructure dust control applications, the risks are that is essential to the prosperity of relatively minor and can be minimized

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About the Author

Gerry Matthews (now retired) was a Senior Account Executive with Occidental Chemical Corporation (OxyChem), responsible for North American sales and marketing of LIQUIDOW™ liquid calcium chloride products. He had over 20 years’ experience assisting highway and road authorities, as well as supporting engineers and contractors, in the effective use of calcium chloride for applications including dust control, road base stabilization, full-depth reclamation, and highway control. Mr. Matthews was a member of the American Public Works Association and a graduate of Central Michigan University.

1 CIA World Fact Book, 2008 data 2 U.S. Census Bureau’s Statistics of U.S. Businesses. 3 Road Dust Suppression: Effect on Maintenance Stability, Safety and the Environment, Phases 1-3; Jonathan Q. Addo, Thomas G. Sanders, Melanie Chenard, 2004. 4 EPA National Ambient Air Quality Standards (40 CFR part 50). 5 Road Dust Suppression: Effect on Maintenance Stability, Safety and the Environment, Phases 1-3; Jonathan Q. Addo, Thomas G. Sanders, Melanie Chenard, 2004. 6 The Incorporation of Dust Palliatives as a Maintenance Option in Unsealed Road Management System, D. Jones, E. Sadzik and I. Wolmerans: Paper from 20th ARRB Conference, 19-21 March 2001. 7 Guidelines for Selecting Dust Suppressants to Control Dust and Prevent Soil Erosion, Michigan Department of Natural Resources and Environment, Office of Pollution Prevention and Compliance Assistance, 2010. 8 Based on U.S. EPA National Recommended Water Quality Criteria: 2002, EPA-822-R-02-047, November 2002.

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