A new report commissioned by the D.C. Water and Sewer Authority and released yesterday did not cite an immediate threat from toxic chlorine at the Blue Plains sewage treatment plant but listed shortcomings in worker safety, maintenance and equipment at the facility.

The report by James V. Dick cautions that the examination was narrow in scope and not intended to address all safety concerns at the facility, which is on the banks of the Potomac River and serves 2 million people. A broader review is underway.

The authority commissioned the Dick report on Nov. 5 in response to an article in The Washington Post that outlined a series of deficiencies in the accident prevention system at Blue Plains. At least 180 tons of chlorine is stored there, and even a small release could have devastating consequences.

On the day The Post's article appeared, Blue Plains officials made several emergency repairs--replacing four of the seven chlorine sensors, enhancing emergency breathing equipment, repairing an audible alarm system, adding nighttime supervisors and beefing up security.

The report by Dick was intended to deal with two central issues: Were authority officials told about safety problems mentioned in The Post report, and did they act properly to correct them? The report concluded that officials were well-informed, but that some problems were not adequately addressed.

The District's acting director of emergency management, Peter G. Laporte, said the Dick report appears to match his own preliminary findings that Blue Plains does not pose an "imminent catastrophic threat." But he said a larger-scale review of safety practices is needed.

"We are specifically interested in addressing overall security, training and emergency evacuation plans," Laporte said in a statement.

The Post article, based on interviews with current and former safety technicians and a review of safety reports, reported that chlorine sensors at the plant did not work properly, workers repeatedly disconnected an audible alarm system, and safety equipment such as breathing apparatus was not properly maintained.

The Post report also prompted a visit to Blue Plains last week by Environmental Protection Agency official Mikal Shabazz. Shabazz, who inspected the plant after the emergency repairs had been made, said in an e-mail accompanying the Dick report that Blue Plains appeared to have a "proactive preventive maintenance program" for its chlorine alarms.

"The facility does not pose an imminent and substantial endangerment to public health or the environment, nor the threat of such," Shabazz said.

However, Shabazz said he has a "major concern" because rail cars holding thousands of gallons of toxic liquid chlorine are "publicly accessible" from the Potomac, presenting a possible target to terrorists. Blue Plains intends to tighten its watch with a roving guard and security cameras, he said. "We are very satisfied that they have their act together, so to speak," he said in a telephone interview.

Dick's report, which did not dispute the facts in the Post article, acknowledged that a technician reported last month that four of the seven sensors had failed a biweekly test. Because no replacements were on hand, it was "many days" before they were replaced. He said the authority needs to improve its inventory system to ensure that such critical parts are available when needed.

There have been five chlorine leaks from the building since 1994, one of which injured four people. Lack of spare parts was a contributing factor. Although there is no common thread to the leaks, all involved mechanical failure and suggest a need for improved inspection and repair, the report said.

In general, though, Dick said chlorine-detecting sensors "appear to have performed properly at all times." Although several sensors were older than their recommended lifespan, the report said that is less important than regular testing, which it said appears to have been done properly.

James J. Bobreski, an engineering technician who was laid off by a firm that does consulting work at Blue Plains after he raised objections about the plant's safety, criticized the authority for hiring a "nontechnical person providing a report on a technical subject. Mr. Dick does not have experience in this."

In particular, Bobreski disputed the conclusions on the chlorine sensors, which are one of the main defenses against a potentially deadly leak. Bobreski said it was his job to calibrate the sensors--a task he said he could not perform because the plant lacked the equipment to do so.

Dick's report cited chronic problems with a panel of alarms in the chlorine building that gave false alarms so often that workers sometimes turned them off. But he said those malfunctions "do not appear to be significant safety-related problems" because the alarms are intended to tell workers whether equipment is working, not to detect chlorine releases. Those alarms also are duplicated on each piece of equipment, he said.

Bobreski said that the failure of the equipment itself is a sign of trouble and that a "low-pressure alarm could indicate a leak. It's just simple physics. It's either low supply or a leak."

Authority officials said yesterday that the central alarm system has been fixed.

Authority Chairman Ron M. Linton argued that the Dick report shows that the Blue Plains plant does not endanger the public or plant workers. "I would sum it up by quoting Shakespeare: 'Much ado about nothing,' " he said.

Linton said worker safety will be addressed as part of the broader safety examination. "I think we are doing a job," he said. "I think we can do a better job."

Dick's report said the chlorine building was left unstaffed "for brief periods on occasion"--mainly because the bathroom there was not usable for several years and the one worker on duty had to go to another building. At least once, an alarm went off while no one was in the building.

Plant policy requires round-the-clock staffing in the chlorine building. Dick, noting this is an important safety issue, said the restroom is now repaired and changes have been made to ensure proper staffing.

The report also took the authority to task over worker safety, concluding it "has not received the priority it deserves." Availability of reliable safety equipment "appears to have been haphazard for at least several years," it said.

One problem is that authority officials address safety concerns as part of talks with unions, "apparently with unproductive results." They should be addressed on their own, the report said. Authority officials say unions are exaggerating worker safety problems in hopes of gaining leverage in contract talks.

As The Post reported, Dick said, emergency breathing masks near the building did not work. Workers and their unions told him that they had complained for years that additional breathing masks kept inside the building did not work properly and that they got no response.

The sewer authority also has authorized plant management to speed up the $18 million conversion from chlorine to a less toxic disinfection method, sodium hypochlorite. Plant officials hope to make the switch in two or three years.

Dick's report found no truth to charges that an equipment maintenance contractor, Givoo Consulting Co., had not conveyed safety concerns to authority officials. After the Post article, the authority suspended its contract with Givoo.

Dick, who will be paid as much as $20,000 for his report, is an antitrust lawyer who received technical help from the consulting firm of Stone & Webster, which is examining overall safety practices at the facility.

Staff writer Eric Lipton contributed to this report.