WATERVILLE (AP) – Mainers who heat their homes with oil may be in for another case of sticker shock as prices approach $3 per gallon this winter.

Summer has barely begun, but people already are pre-buying heating oil or entering into budget deals at prices that are up around $2.70.

Jamie Py, president of the Maine Oil Dealers Association, said prices for pre-buy or budget plans are up about 20 percent across the state over the levels a year ago. Py said the prices reflect world events that have led to tight oil supplies, causing wholesale prices to soar.

J&S Oil, which has offices in Winslow and Manchester, has set a pre-buy price of $2.69 per gallon for new customers who don’t qualify for discount programs the company offers.

At OSM Fuel in Skowhegan, the pre-buy price went from $2.19 to $2.69, a nearly 19 percent increase. Webber Energy Fuels, which has offices in Augusta and Gardiner, says its special contract price has been bouncing from $2.50 to $2.70.

Mike Shey, president and chief executive officer of Webber Energy Fuels, said this year’s price increases may not be popular, but they don’t pack the same wallop as they did a year ago when prices shot up due to disruptions stemming from Hurricane Katrina.

“I think last year was the real sticker shock year,” Shey said, “and even though this year the price is up again, it is not incrementally up as much as last year.”

To help stretch supplies last winter and keep vulnerable Mainers warm, the state signed a deal in which Citgo, the Houston-based subsidiary of Venezuela’s state-owned oil company, sold 8 million gallons of heating oil on the open market and donated what amounts to a 40-percent discount to Maine.

The state Legislature also moved quickly to increase funding to the state’s heating assistance program early in this year’s session.

The winter turned out to be warmer than usual, providing welcome relief for many Mainers.