August 30, 2011
Exponent's white paper entitled "Methanol Use in Hydraulic Fracturing Fluids" was released today by The Methanol Institute. With increasing public attention on hydraulic fracturing operations, the Methanol Institute commissioned the white paper to examine the fate and transport of methanol in hydraulic fracturing operations. Exponent's white paper supplements the original 1999 Malcolm Pirnie1 report that provided information on the general fate and transport behavior of methanol in the environment. The report focused on the use of methanol in hydraulic fracturing (also known as fracking) fluids: role, volumes used, and the determination of whether the use of methanol in fracking fluids could result in exceeding its corresponding health-based screening levels in drinking water and surface water. Although this report is focused on the USA where most fracking is taking place, the report has global applicability for its findings.
Methanol is a common chemical commodity and alternative transportation fuel. Methanol has many chemical characteristics that make it an important additive to fracking fluids (e.g., corrosion and scale inhibitor, and friction reducer). Currently, the volumes of methanol used per fracturing job are on the order of hundreds of pounds, a small fraction of the total fracturing fluid volumes used. Even though there has not been a documented case of methanol contaminating the environment as a result of its use in fracking, Exponent's consultants evalated hypothetical scenarios of methanol impacting groundwater (as a result of fracking fluid leakage from a well casing) and surface water (as a result of the discharge of treated flowback). The scenarios show that methanol concentrations in groundwater and surface 1-2 water are expected to be several times lower than the health-based screening levels for methanol.
Exponent's health scientists also calculated health-based screening levels for both groundwater (residential drinking water consumption) and surface water (recreational incidental ingestion). These screening levels are applicable to the pathways of exposure to methanol as part of fracking fluids, including 1) consumption of groundwater impacted by methanol-containing fracking fluids, and 2) incidental ingestion of river and stream waters that received treated flowback. The estimated methanol intake as a result of exposure to these pathways is several times lower than the health-based screening levels for methanol.
The Methanol Instituted noted the following in its August 30th press release. "When conducted properly, fracking is a safe and strategic operation that is rapidly expanding the world's access to natural gas," said Methanol Institute Executive Director Gregory Dolan. "Methanol is a biodegradable chemical and an essential component in the fracking process that for all practical purposes poses no risk."
The text of The Methanol Institute's press release can be found here.
The entire Exponent white paper can be found here.
1. Malcolm Pirnie. 1999. Evaluation of the fate and transport of methanol in the environment. Prepared for the American Methanol Institute. Malcolm Pirnie, Oakland, CA 94612.