Possible new dump sites for hazardous waste in Maryland, needed to replace two nearly full landfills near Baltimore that are due to close next year, will be announced within the next few weeks by the Maryland Environmental Service (MES).

Because Baltimore produces 90 percent of the state's toxic wastes and nearby sections of Anne Arundel County are responsible for another 6 percent, it is considered "politically unlikely" that the state's Hazardous Waste Facilities Siting Board will choose a dump site far from Baltimore, state officials said privately last week.

The siting board announced last month that "to minimize . . . the expense and risk to the general public of long-distance transport of hazardous materials . . . the disposal needs will best be met through facilities whose location takes into account these concerns."

The board will hold a public hearing Nov. 4 in Annapolis to hear comment on a year-long study of the state's hazardous waste problems and on the board's decision that a new landfill "is an absolute necessity" to dispose of the 135,000 tons of solid hazardous wastes produced annually in Maryland.

The landfill must be large enough (around 500 acres) to take 200,000 tons a year for at least five years. This will allow flexibility and space to handle out-of-state wastes, which states legally cannot exclude and which are hard to estimate.

In 1980 Maryland disposed of 55,000 tons of out-of-state hazardous wastes in addition to 300,000 tons generated by industries in the state. These non-nuclear wastes included acids, lyes, toxic gases and liquids and anything that presented a hazard of fire or explosion.

Public meetings will be held later in November on possible locations for the new landfill. The meetings will follow the MES announcement of an "inventory" of possible dump sites in the state. State officials said last week no dates for the announcement or public meetings have been set.

Maps released this summer showed site "search areas" on about one-fourth of Prince George's County, and state officials said at the time that several regions, particularly along Rte. 301, were likely candidates for the final landfill selection.

Some of Montgomery County's most densely developed suburbs -- Bethesda and Silver Spring north to Olney -- also were shown as "search areas" for possible dump sites. They were chosen by geologists and engineers largely because of their topography, but state officials said these Montgomery sites would almost certainly be eliminated because of the population density. Other parts of Montgomery were eliminated because of danger to the county's water supply and to parkland.

As a policy matter, the siting board has said it plans to impose conditions on state industries that "expedite, enhance or enforce" methods of disposal other than land burial. But only a small portion of the hazardous wastes are burnable in incinerators or adaptable to reuse or recovery techniques.