Nearly a year after D.C. Mayor Marion Barry vowed to reduce a backlog of 6,000 applications for certificates of occupancy -- the city's testament that a building is safe -- city officials have failed to dent it.

"It's a serious problem," said Robert Lewis, head of the city department that issues the certificates. "We have a potential problem where 6,000 establishments can cause harm or danger to people" because of possible violations of the city's fire and building codes.

Barry's pledge to reduce the backlog came after 10 women outpatients from St. Elizabeths Hospital were killed in a fire last April at a group home on Lamont Street NW -- the worst fire in the city's history. The home had a certificate of occupancy, but city officials said after the fire that it should have not been issued because the house had several fire code violations.

With such a large backlog of applications, the city doesn't know whether the 6,000 businesses are operating in violation of city law or whether they are closed up, because no inspectors have visited the addresses on the outstanding applications recently.

The city requires that every owner of a business of multi-family dwelling obtain a certificate of occupancy, the guarantee that the building is safe before it opens its doors or when it changes owners.

A reporter visiting 10 addresses with outstanding applications found that while six of the buildings were empty or had new businesses with valid permits, businesses were operating at three others without a valid certificate on hand. One address was incorrect.

For example, the law firm of Miller and Loeninger applied for a certificate in August 1976 for its offices at 471 H St. NW. According to city records, the certificate has never been granted. But the law firm is open for business.

Kenneth Loeninger, one of the firm's partners, said he would not comment because the firm is in litigation with the contractor who restored the building.

The N&S auto repair shop at 607 K St. NW applied for a certificate in January 1977 and never received it, according to city records. But the shop is open. Manager George Nicholas said he thought he had received the certificate, but could not find it.

The application for the third address -- the first floor of 802 F. St. NW -- was for a wig shop that is no longer there. But the business now occupying the site, The Studio Gallery, does not have a valid certificate, according to city records.

Val Lewton, a member of the gallery's governing board and its former president, said he never obtained a certificate because he did not understand the city application forms. But he said that he has obtained a second set of forms and will submit them.

A person who owns or operates a business without a valid certificate of occupancy may be subject to a $300 fine or 10 days in jail or both for each day the business is open without it.

Lewis said his department intends to take action against businesses that "through their own negligence" never obtained a certificate. If the city was at fault for not issuing a certificate, then no action will be taken, he said.

Lewis said "some progress" has been made on the backlog by tediously hand-checking applications against addresses for buildings that have current certificates. In some cases, the department found that an owner had reapplied and been granted a certificate without canceling the old application.

In other cases, it was found that the buildings involved had been demolished or converted to use as single-family homes.

But while that process reduced the backlog by 4,000 applications, the city found that it actually had a backlog of 10,000 applications. And so the city still has 6,000 outstanding applications in its files, just as it did a year ago.

"This is an accumulation from years and years where inspectors would go out and they could not get in a building or where they found violations," said Ernest L. Pifer, director of the department's permit section, which is directly responsible for issuing the certificates.

But Pifer's office can't issue the certificates until inspectors from seven or eight city departments approve a building.

"Part of the problem is that now we send out seven inspectors to inspect a different thing in one building," Lewis said. "The present process is inefficient" and time-consuming, he said.

Frank Emmet, a real estate property manager who has 30 applications pending with the city, some of which are more than 14 months old, agreed.

"This is where there are too many kinks in the process, trying to schedule all these people to come to a building. Sometimes two will come and sometimes none will show up."

A special task force of inspectors created group homes after the Lamont Street fire to review such group homes, was assigned March 12 to tackle the backlog. The inspectors are trained in several inspection fields.

Lewis said his department also intends to institute a new policy over the next few months in which all new applications would become invalid if not approved within 90 days. That way, new applications that have not been resolved presumably would not pile up. After 90 days, an owner would be required to submit a new application.