The Army will announce Tuesday that its "preferred alternative" for disposing of obsolete chemical weapons is to burn them at the eight sites where they are now stored, including Aberdeen, Md., rather than shipping them to one or two central locations for destruction, Defense Department officials said yesterday.

The officials, who asked not be identified, emphasized, however, that no final decision will be made until January, after three months of public hearings and further studies. By law, the weapons must be destroyed by 1994.

Officially, Army spokesman Maj. Phil Soucy would only say that three options are to be listed Tuesday. But other defense officials said that an environmental impact statement to be released will lay out three options for getting rid of the old chemical weapons, and will say the Army prefers incinerating the weapons in place.

Whatever the ultimate decision, it is expected to produce opposition from residents of several of the eight sites where the weapons are stored, or from communities along the expected transportation routes that would be used if the chemical weapons are shipped to other locations for disposal.

In addition to Aberdeen, the storage sites are in Utah, Alabama, Kentucky, Indiana, Oregon, Colorado and Arkansas.

The bulk of the stockpile stored at Aberdeen is mustard nerve agent, a potent carcinogen with no safe level of exposure, which can also cause swelling and blistering of the skin, eyes and lungs.

Destruction of the old weapons was ordered by Congress last year when it authorized production of new chemical weapons for the first time since 1969.

The three options to be listed Tuesday are:

* Destruction at the sites.

* Shipment of weapons to two central regional sites for final disposal -- Anniston, Ala., Army depot for those now stored in the eastern part of the country, and Tooele Army depot near Salt Lake City.

* Shipment of all the stored weapons to Tooele.

The Army's preference for on-site burning was first reported by the Associated Press June 18, which said that the Army was "likely to recommend incineration at the eight existing sites." The New York Times reported yesterday that the Army would declare Tuesday that on-site burning was its preferred alternative. It said Rep. Larry J. Hopkins (R-Ky.), whose district includes the Kentucky storage site, had said the Army had told him at a briefing of its preference.

Although Soucy would not would not confirm this report yesterday, he noted, according to wire service stories, that the Army had indicated its preference for on-site burning two years ago.