The Corporation’s principal business serves customers in aggregates-related construction markets. This concentration could increase the risk of potential losses on customer receivables; however, payment bonds normally posted on public projects, together with lien rights on private projects, help to mitigate the risk of uncollectible receivables. The level of aggregates demand in the Corporation’s end-use markets, production levels and the management of production costs will affect the operating leverage of the Aggregates business and, therefore, profitability. Production costs in the Aggregates business are also sensitive to energy prices, both directly and indirectly. Diesel fuel and other consumables change production costs directly through consumption or indirectly by increased energy-related input costs, such as, steel, explosives, tires and conveyor belts. Fluctuating diesel fuel pricing also affects transportation costs, primarily through fuel surcharges in the Corporation’s long-haul distribution network. The Specialty Products business is sensitive to changes in domestic steel capacity utilization and the absolute price and fluctuations in the cost of natural gas. However, due to recent technology developments allowing the harvesting of abundant natural gas supplies in the U.S., natural gas prices have stabilized.Transportation in the Corporation’s long-haul network, particularly rail cars and locomotive power to move trains, affects our ability to efficiently transport material into certain markets, most notably Texas, Florida and the Gulf Coast. The availability of trucks to transport our product, particularly in markets experiencing increased demand due to energy sector activity, is also a risk. The Aggregates business is also subject to weather-related risks that can significantly affect production schedules and profitability. The first and fourth quarters are most adversely affected by winter weather, and the operations in the Denver, Colorado, market increase the Corporation’s exposure to winter weather. Hurricane activity in the Atlantic Ocean and Gulf Coast generally is most active during the third and fourth quarters.