Oil prices and related exchange traded funds (ETFs) continued the see-saw, wavering a little today.

Gas dropped below $4.07 a gallon (hooray!), while oil rose by a scant 8 cents to $136.82 a barrel, reports John Wilen for the Associated Press. But any gains that might have been made are being held back, thanks to worries about demand paired with Congress’ intensifying look at the oil market.

Among the actions Congress is exploring are closing loopholes in foreign oil trading, limiting hedge funds from putting money into the market and ending oil speculation altogether. Nine different bills on speculation have been introduced, and that doesn’t even include the ones that tackle other causes of rising prices, reports David Goldman for CNNMoney.

Meanwhile, former Federal Reserve Chairman Alan Greenspan warned that the U.S. economy was on the brink of a recession and put the chances for recession showers at 50%, says Stella Mapenzauswa for Reuters. Greenspan dashed hopes for a quick recovery, as well, saying that it was unlikely.

As the markets wait for hints on what’s going to happen with oil and other energy commodities, the related ETFs are sitting tight:

• United States Oil (USO), up 46.4% year-to-date
• United States Gasoline (UGA), up 29.9% since Feb. 28 inception
• United States Natural Gas (UNG), up 73.4% year-to-date

Tags: Energy, Federal Reserve, Green ETFs, Natural Gas, Oil, UNG, USO