The National Wildlife Federation called on Michigan and Ohio to strengthen laws regarding water withdrawals for hydraulic fracturing and recommended operators examine the potential toxicity of the fluids used during the process.
Energy companies have moved into deeper shale natural gas deposits as technology improves. This, the NWF said, means they need more freshwater for their operations, which could lead to problems with well wastewater.
"Our analysis shows that Michigan and Ohio are doing some things right but the states remain vulnerable to risks associated with fracking," Sara Gosman, an attorney for the National Wildlife Federation's Great Lakes office, said in a statement.
Hydraulic fracturing, known also as fracking, is the process in which water laced with abrasives and chemicals is injected into underground rock formations to extract natural gas. Some of the chemicals used in the process are toxic, though they're typically present in trace amounts.
The process isn't regulated at the federal level, meaning it's up to the states to take precautionary steps to ensure the practice is safe.
"Our thorough review of the laws shows that Michigan and Ohio have taken significant steps, but they need to do more," said Gosman.