An article in yesterday's editions of The Washington Post on the heating oil supply for next winter reported incorrectly the figures a Department of Energy official used in congressional testimony on the subject. The department's Douglas Robinson actually said that refiners will be asked to increase the proportion of heating oil produced from each barrel of crude oil from 21.5 percent to 23 percent. This would require a reduction in the amount of gasoline produced from each barrel of crude.

A leading Washington area oil supplier warned yesterday that area residents - already plagued by gasoline shortages - face a home heating fuel shortage this winter unless local pollution standards are relaxed to permit commercial use of lower grade fuel.

Leonard P. Steuart II, president of Steuart Petroleum Co., said his own stockpiles of so-called middle distillate or No. 2 home heating fuel are smaller now than they were a year ago and demand is greater.

"Our inventory at the moment is about 8 million gallons, which is slightly less than this time last year," Steuart said, "and we're being asked to supply more." Steuart's bulk storage tanks at Piney Point, Md., when full, hold 60 million gallons.

Steuart's warning of possible winter shortages coincided with disclosure by federal energy officials that home heating fuel stocks throughout the nation appear to be abnormally low and are being built up very slowly. A Department of Energy (DOE) memorandum to the White House cited recent crude oil shortages from overseas as a primary cause and urged a number of conservation options to ease the problem.

Steuart is scheduled today to testify before a D.C. City Council committee on local fuel dupply problems. In his prepared statement, he urges that the federal government, utilities and other major home heating fuel customers convert from No. 2 oil to the cheaper but dirtier No. 6 residual oil. Conversion would require an emergency declaration by Mayor Marion S. Barry and a formal request to President Carter for temporary suspension of current pollution emission standards.

Relaxation of standards is also one of several options recommended in the DOE memo to the White House. Other options include discouraging hoarding of home heating fuel by major users such as utilities, limiting amounts available for peak use during the upcoming summer and ordering refiners to produce more heating oil at the sacrifice of other kinds of fuel.

Of the various options, relaxing pollution standards appear the simplest and perhaps the most advantageous for Steuart, among the biggest suppliers in the Washington area.

Steuart acknowledges in his prepared statement that the supply of No. 6 oil "is not so critical" as that of No. 2, and a competitor of Steuart said yesterday that Steuart's overseas supplier has more No. 6 available than some of the other importers.

In a telephone interview, Steuart said he had no figures for current or anticipated stockpiles of home heating fuel for the immediate Washington area. But he cited DOE national estimates showing there are only 126 million barrels in current stocks, more than 100 million barrels short of DOE's primary stock target" of 240 million barrels by Oct 1.

"It should be noted," Steuart said in his statement, "that in the time since the 240 million barrel goal was announced in April, stocks have increased only 13 million barrels. In sum, we have a long way to go."

Ed Murphy, a statistician for the American Petroleum Institute, said 240 million barrels of home heating fuel should be enough "and possibly more than we need" to get through the winter.

The question is whether that goal can be reached. The country will have to stockpile an additional 110 to 112 million barrels between now and Oct. 1 - a rate of more than one million barrels a day.

In 1977, "a relatively normal year," Murphy said, the country had to increase stocks a somewhat similar amount - from 162 million barrels at the end of May to 253 million by the end of September.

"But then there was plenty of crude available and there was no gas shortage," he said. "It depends on the availability of crude."

While official opinion has varied on that question in recent weeks, Steuart said in his statement, "No crystal ball is necessary to see the supply crisis looming."

He said, "The inventory buildup is not proceeding according to schedule. As a result of several factors - reduced domestic refinery runs of crude oil pressures to produce other products and the immediate needs of farmers and truckers and others - home heating oil stocks are depleted and are not being rebuilt at a satisfactory pace. Unless this trend is reversed, a serious supply shortage is likely."

He said mandatory gasoline conservation and cutbacks in gasoline production to allow greater production of home heating fule are only partial solutions.

Far more effective, he said, would be a widespread substitution of No. 6 residual fuel for home heating oil, for use by the federal government, the Potomac Electric Power Co. and other major consumers here. He estimated at least 2 million barrels of No. 6 residual oil could be used this way, freeing up 2 million gallons of home heating oil - that could supply some 70,000 area homes for the entire winter. There is a total of more than 200,000 oil-heated homes in the Washington area, he said.

Pepco, he noted, used almost 700,000 barrels of home heating oil in the District of Columbia last year.

To meet stringent D.C. emission standard, Pepco burns a blend of No. 2 home heating fuel and No. 6 residual oil called "No. 4" fuel at its main plant on Benning Road NE.

If emission standards were suspended to allow only No. 6, increased pollution would be "miniscule," Steuart said yesterday. He acknowledge that he could "not quantify" the increase, "but it is my judgment that it would be minor."

Pepco estimates the Benning Road plant and a backup plant at Buzzard Point contribute only about 2 percent of the city's particiulate pollution. The rest, a company spokesman said, comes from construction sites, auto emissions and building demolition.

Steuart said No. 2 home heating fuel could be replaced with No. 6 oil at Pepco and in federal government buildings, various suburban county school buildings and other commercial facilities for a total diversion of 2.3 million barrels of home heating fuel to private homes. In addition, he said, the lower cost of No. 6 would save the area $6.3 million in fuel costs.