Is it safe to trust the nation's oil and gas companies with our fragile environment? BP's (NYSE: BP) 2010 Gulf of Mexico tragedy aside, if you've followed the enlivened brouhaha this week about diesel fuel possibly being used in hydraulic fracturing -- aka fracking -- you likely think not.

As you've undoubtedly learned, fracking involves drilling into hard rock or shale, and then blasting water, sand, and other fluids into the well bore. The shale is then broken up, releasing the oil or gas trapped inside.

The latest contentious round on the subject reached a crescendo this week when three members of Congress, Henry Waxman of California, Edward Markey of Massachusetts, and Diana DeGette of Colorado, penned a letter to Environmental Protection Agency Administrator Lisa Jackson.

In their missive the trio contend that a pair of the biggest oilfield services companies, Halliburton (NYSE: HAL) and Baker Hughes' (NYSE: BHI) BJ Services unit, are part of a 12-company contingent that injected 32.2 million gallons of diesel or fluids containing diesel into wells in 19 states during the 2005 to 2009 period.

As the representatives noted in their letter, "This appears to be a violation of the Safe Drinking Water Act. It also means that the companies injecting diesel fuel haven't performed the environmental reviews required by the law." All of the companies, including industry kingpin Schlumberger (NYSE: SLB), agreed in 2003 to desist from using diesel in fracking fuels for coalbed methane production wells, which typically are drilled nearer to drinking water sources.

Halliburton has responded that it "is firmly committed to meeting all of the regulatory requirements applicable to hydraulic fracturing."

In December, I told Fools that Halliburton, Baker Hughes, and smaller Flotek (NYSE: FTK) all are in the nascent stages of producing safer fracking fluids comprised of ingredients used in food or health-care products. Despite (or perhaps because of) my roots in Texas -- the target of fully half the total diesel fuel used in fracking -- I agree wholeheartedly with a stance taken by my Foolish colleague Alyce Lomax.

In an excellent article last month, she observed that numerous "socially responsible investors have filed resolutions related to fracking at many major oil companies ..." Included among the resolutions' targets are the two largest U.S.-based members of Big Oil, ExxonMobil (NYSE: XOM) and Chevron (NYSE: CVX).

For my money, Alyce was dead on when she urged that, "All investors should pay attention to shareholder resolutions filed at the companies they own." Approaching the possible transgressions in that manner is far more likely to yield meaningful results than are elected officials who may be headed off half-cocked.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.