D.C. corrections officials said yesterday that a total of about 900 inmates will be released early from D.C. prisons and halfway houses because of the prison crowding crisis -- more than twice the number originally estimated when Mayor Marion Barry invoked the emergency release program earlier this summer.

Corrections Director Hallem H. Williams Jr. said that since Barry declared the emergency on July 3, 483 inmates convicted of nonviolent crimes have been released, and he expects an additional 417 to be released by the end of September, when the 90-day emergency measure ends.

Corrections officials initially predicted that only 350 inmates would be released under the program.

Williams said the original estimate included only inmates who already had been sentenced at the time the program began. Hundreds of inmates sentenced since July 3 also are eligible for early releases, Williams said.

Williams said that corrections officials "did not focus" on the numbers of newly sentenced prisoners whose sentences would fall within the qualifications for early release.

Under the measure, Barry is allowed to reduce by 90 days the minimum sentences of some inmates convicted of nonviolent crimes, making them eligible for early parole.

Barry is also permitted to reduce by 10 percent or up to a total of 90 days the sentences of inmates convicted of nonviolent crimes who are serving their maximum sentences. Generally, these prisoners were either denied parole at some point or chose to serve their full sentences rather than be under parole supervision later.

Prisoners convicted of violent crimes -- including homicide, rape, assault with a dangerous weapon and armed robbery -- and those serving mandatory sentences on drug convictions do not qualify for early release.

About 70 percent of all inmates who have been released early would have been released by now even if the emergency had not been declared, and 30 percent of the inmates would still be in prison, Williams said.

The most frequently cited crime among the first 134 inmates released was drug possession, corrections officials said. Other offenses by the inmates released early from District prisons included those of carrying pistols without licenses, attempted distribution of PCP, car theft, theft, assault without a weapon, destruction of property, distribution of marijuana, prostitution, burglary, robbery, larceny, bail violation, driving while intoxicated and other driving violations.

The department has not disclosed any information on the additional 349 inmates released or the crimes they committed.

Since the emergency was declared, the total prison population has dropped by only about 2 percent from 7,950 on July 3 to 7,824 as of Friday, corrections officials said. The rapid flow of new prisoners into the system has offset much of the gain from the emergency measure, he said.

Still, Williams said that the measure has had a "calming effect" on the institution.