Heine’s group is sifting through company disclosures to perform a risk assessment on the most commonly used chemicals. The effort is designed to provide a single point of comparison so that scientists, industry and the public can make informed decisions about which chemicals are best.
Daniel Durham, who heads a chemical-assessment program at the Houston-based energy company Apache, says that although Heine’s effort is promising, companies do not need to wait. The US Environmental Protection Agency (EPA) already maintains its own public registry of preferred chemicals for various industrial processes. Companies that want to register their chemicals provide the EPA with toxicity and environmental-assessment data; the registry also allows companies to keep certain data confidential if intellectual property is involved.
The upshot is a growing — albeit incomplete — list of preferred chemicals that companies such as Apache can choose from as they design their fracking fluids. A company that wants to avoid using a solvent such as ethylene glycol monobutyl ether, for example — used to reduce viscosity but possibly toxic to the endocrine system — could look through the EPA list for alternatives. “It’s a very good road map to green chemistry,” Durham says.
Eventually, Durham hopes that researchers will help to develop novel chemicals that could be used to make the entire hydraulic-fracturing process cleaner and more efficient. Scientists such as Ellis could play an important part.
Ellis wants to know whether fracking fluids are contributing to geochemical reactions within the shale rock that might free up potentially dangerous metals and radionuclides, such as arsenic, barium, strontium and uranium. These elements are often found in trace concentrations in the waste water produced by oil and gas companies, but can also be found naturally in groundwater. Ellis eventually hopes to help companies to select better chemicals that would minimize the potential for contamination and the need for waste-water treatment. But for now, he says, he is focused on the basic science. “Fundamentally, I just want to understand those reactions a little better.”