Track 2: Sustainability and Conservation of Built Heritage in the Americas
As considerable amounts of crude oil circulate North America by truck, rail, and pipeline, spills are inevitable. Such incidents lead to indiscriminate contamination of surrounding environments, including historic buildings. Despite the physical and chemical damage associated with crude oil contamination, little is understood about how best to respond to this type of spill. Relative to professionals in the cultural resources sector, oil spill responders are more familiar with the properties of crude oil and the products designed to clean or contain it. Yet, few of the methods preferred by first responders, including power washing and large-scale application, are appropriate for historic buildings. The situation is further complicated by oil spill response protocol, which requires that products be selected from the Environmental Protection Agency’s National Contingency Plan Product Schedule in order to be applied in situ. Beginning in January 2018, this 2 year project aims to identify (1) commercial products from the EPA NCP Product Schedule and (2) application methods best suited to remove crude oil contamination from historic buildings.
Oils of varying viscosity, the primary property used to classify crude oil, are examined, including medium-viscosity West Texas Intermediate and heavy Access Western Blend diluted bitumen. While West Texas Intermediate represents the relatively less dense oils that have been involved in traditional spills, information about the challenges presented by diluted bitumen has become increasingly important in the United States as rising levels of production and transportation increase the risk of related spills. Diluted bitumen or “dilbit” describes bitumen that is extracted from oil sands and diluted with lighter density hydrocarbons to facilitate travel by pipeline. The unique composition of this conglomeration of heavy bitumen and lighter condensates poses a unique set of challenges to historic materials; as the condensate evaporates rapidly, a heavy bituminous residue remains. As oil companies continue to direct money and resources towards further expansion of “dilbit” facilities, the present examination of treatment application, products, and timeline becomes increasingly important.
This study examines treatments for historic brick, concrete, Douglas fir, and yellow pine. By necessity, the research explores methods for classifying oil response agents, simulating the process of oil contamination in a laboratory setting, and assessing the long-term effects of oil contamination for occupied historic buildings. Success is measured by data describing the color, gloss character, surface roughness, and aptitude for water vapor transmission of surrogate historic materials before and after exposure to oil as well as after successive treatments. This research is being carried out by the National Center for Preservation Technology and Training as part of the U.S. Department of the Interior Inland Oil Spill Preparedness Project (IOSPP).