The Department of Housing and Urban Development has proposed new rules for removing lead paint hazards from all government-assisted housing, but decided it was not "practicable" to remove the paint in single-family homes insured by the Federal Housing Administration, even though a federal judge has ordered it to include such houses in the paint removal plans.

U.S. District Judge Gerhard A. Gesell's order said single-family homes, privately owned apartment buildings constructed with federal assistance and apartments leased with rental assistance certificates were to be covered by the new regulations.

The court order stems from a 1981 lawsuit against HUD in which Gesell ruled that the department's lead paint removal regulations fell short of what Congress intended when it passed the Lead-Based Paint Poisoning Prevention Act.

Cheryl C. Burke, an attorney representing the District of Columbia public housing tenants who sued HUD seeking removal of the lead paint in their apartments, said that in the proposals affecting rental assistance programs, as in some other suggested regulations, "the effect is to make children the testing machines. Children who are healthy when they move in will have no protection from lead paint in the dwellings. I object to that on moral grounds."

The suit against HUD was filed after a 2-year-old girl living in Stanton Dwellings in Southeast Washington was hospitalized with lead poisoning. An estimated 200 children die from lead poisoning each year and another 10,000 or more become ill.

Current HUD regulations provide for removing lead paint if it is flaking or cracking, but Gesell ruled new regulations must be implemented to provide for elimination of intact, or "tight," paint.

In the proposed regulations published last week in the Federal Register, HUD said it would test for and remove tight paint from some multifamily rental housing receiving federal assistance.

The poisoning prevention law requires the government to remove lead paint hazards "as far as practicable."

HUD general counsel John J. Knapp said the FHA insurance program cannot meet the standard with regard to intact paint. He said "the court order doesn't supersede the statute."

Burke said she would file comments protesting HUD's interpretation of the law.

The department also proposed to limit its lead paint testing and removal in the rental assistance units to those occupied by families with children who already have elevated levels of lead in their blood.

Proposed rules issued in February for public and Indian housing called for removing intact paint containing 0.7 milligrams or more of lead per square centimeter from "chewable" surfaces, such as corners of walls, doors and woodwork.

The proposals say cracked or flaking paint on surfaces where it is an "immediate hazard" is to be removed. Cracked paint on surfaces 5 feet above the floor and intact paint on flat surfaces are classified as potential hazards, to be checked at least yearly.

About 2 million home buyers a year apply for FHA mortgage insurance, and it is estimated that about 1 million of their homes might have lead-based paint. HUD estimates that about half of the nation's 1.3 million public housing units contain lead-based paint.

But there are only about 400 machines in the United States for testing the lead content of paint. And about 8,000 appraisers, who would be responsible for ensuring that homes are free of lead paint hazards, work in the FHA insurance program. Knapp said current rules requiring removal of chipped and peeling paint from FHA-insured homes will be continued.

The scarcity of testing equipment also is a large factor in limiting the rules covering housing leased with federal rental-assistance certificates, as is the belief that blood-screening facilities and testing machinery are likely to be available in large cities, where most children with high levels of lead in their blood are found, Knapp said. The so-called Section 8 rental assistance is the federal government's largest housing aid program for the poor.

The proposed rules say HUD will decide whether testing and abatement programs will be limited to housing built before 1950 or will include all structures built before 1978 after a 60-day comment period before the rules become final.

The proposed rules say that "considerations which would be relevant" to the decision include information from lenders, real estate industry members, public housing officials who administer rental assistance programs and local health agencies about possible effects on "program participation and benefits and the correlation between elevated blood levels in children and the lead content of paint."

The lead poisoning act requires the government to remove lead paint hazards from federally insured and subsidized housing built before 1950 because interior paint used before that date contained high levels of lead, 50 percent in some cases. But it makes hazard abatement programs optional for housing constructed later. Paint manufactured after 1950 contained smaller percentages, and all use of lead was banned in 1977.

In a recent study of public housing units, commissioned by HUD, 69 percent of the units built before 1950 were shown to have lead levels in paint of more than 1 milligram per square centimeter, while 48 percent of those built between 1951 and 1959 and 44 percent of units constructed between 1960 and 1977 had the same level, according to comments published with the proposed regulations last week.

Burke said that because lead levels are this high in public housing, other structures built during the same periods are likely to have similar levels and should be covered by more stringent rules than HUD is now proposing.

Opponents of the more extensive requirements have argued that the cost would become prohibitive, driving private owners of federally assisted housing out of the programs and making housing for low-income families scarcer.

The Office of Management and Budget has objected to the potential cost of extensive lead abatement rules and to HUD's proposal to use 1978 as a cutoff date instead of 1950, which is all that is required by law. OMB Director James Miller said earlier this year that HUD's proposed regulations for public housing would cost the government "at least $600 million to $1 billion over the next five years and will generate benefits of less than $200 million."

OMB, which reviews all government agencies' proposed regulations under the Paperwork Reduction Act, has given temporary approval to the proposed rules issued in Feburary, and to those issued last week, and will review the regulations before they become final.

The U.S. Court of Appeals, in upholding a district court decision, said HUD in the past has "erroneously placed too much emphasis on cost-effectiveness in determining the practicability of hazard-elimination measures." Attorney Burke said she agrees with that opinion. "What HUD never seems to grasp" is that what is not practicable next month or next year could be done over a longer term, "so instead of setting a timetable they say it is not practicable now, so we will never do it," she said.

She also questioned the seriousness of a shortage of testing equipment, saying more could be manufactured if it were needed.

The American Academy of Pediatrics, commenting on the proposed rules for public housing that were published in February, suggested that all federally owned and assisted housing, no matter when it was built, should be tested and hazardous paint removed. It said such a process would be expensive, but would be a one-time opportunity to get rid of all lead paint dangers.

The Centers for Disease Control reported last year that new research showed children could be poisoned by lead levels lower than previously dangerous. CDC has dropped its definition of the toxic level from 30 to 25 micrograms of lead per decileter of whole blood.