For Fairfax County fire officials, disillusionment with Underwriters Laboratories Inc. began in November 1996 with a brief story in Sprinkler Age magazine. The story said UL was investigating reports that the popular Omega fire sprinkler was malfunctioning.

With thousands of Omegas in hundreds of Fairfax buildings, including schools and hospitals, county officials promptly asked UL for its test results. UL declined, saying they were proprietary. But, UL added, Fairfax officials needed to start testing Omegas in county buildings.

"Here is one of the largest fire departments in the country requesting information on a life-safety issue and UL says it can't give us that information," said Fairfax Fire and Rescue Department Capt. Frank Teevan. "If they say public safety is their primary mission, then their loyalty should have been to us and the public. That simply wasn't the case; UL was the guardian for the manufacturer."

That was just the beginning of Fairfax's two-year battle with UL and Omega's manufacturer, Central Sprinkler Co. In October 1998, about 8.4 million Omega sprinklers were recalled, settling a lawsuit filed by the Consumer Product Safety Commission against Central. The CPSC said the sprinklers had a basic defect that could make them fail to operate during a fire.

The repercussions of the recall still linger. UL has changed some of its testing procedures and has indicated it may stop approving any sprinklers made with O-rings, which were considered the major cause of Omega's problems. Meanwhile, the CPSC has launched a probe into other models and into UL's standards to see if more revisions are needed to ensure long-term reliability. And at a Nov. 16 meeting with sprinkler manufacturers, CPSC staff members asked the industry to hire an independent company, with more expertise in the area than UL, to do extensive testing on sprinklers.

CPSC Chairman Ann Brown still bristles at how UL dealt with the defective Omega. "When it became apparent in 1996 and 1997 that Omegas were failing in massive numbers, UL publicly sided with Central's self-serving explanations and suspect remediation programs," Brown said.

Debra Rade, UL's chief legal officer and senior vice president of administrative operations, said UL "acted very responsibly."

"As soon as we found out there was a problem, we began to investigate immediately. We mounted an enormous effort to conduct field tests and hired outside metalurgical specialists to identify the problem, all at our expense," she said.

Central declined to comment.

Officials at the National Fire Sprinkler Association say there's no indication of a widespread problem with sprinklers and there have not been any deaths associated with their malfunctioning. But Fairfax fire officials have been left with doubts about UL-approved products.

Had UL done a minimal amount of research, Teevan said, it would have discovered that some of Omega's components could deteriorate over time as they reacted with chemicals and contaminants commonly found in sprinkling systems. "Within one day of research, we had enough information in writing" to indicate that the rubber O-ring was incompatible with some hydrocarbons found in sprinkler systems, he said.

UL said it had performed extensive testing on the sprinklers to see how they would perform in different environmental conditions, and it had no information to indicate hydrocarbons would pose a problem in sprinkler systems.

Omegas were sold between 1983 and 1998 and installed across the country, including in national hotel chains, Department of Veterans Affairs hospitals, Smithsonian Institution buildings, the White House and Congress. Problems first surfaced in 1995, when they failed to operate in two fires.

In April 1996, Central blamed the failures on an unusual situation in which stop-leak products (such as those used to stop leaks in auto engine cooling systems) were erroneously placed in the sprinkler systems. "It is Central's belief that both of these situations are uncommon," Central said in a statement, adding that the Omega continued to carry UL's approval.

A few months later, UL announced its own investigation of Omegas, spurring Fairfax fire officials into action. Over the next few months, Fairfax officials pulled more than 700 Omega sprinklers from buildings and sent them to an independent lab; 35 percent of them failed to operate at the minimum water-pressure standard, Teevan said. Similar results were reported by major hotel chains, large property-management firms and government agencies.

In May 1997, UL said it had tested more than 800 Omegas. Of those, 31 percent failed to operate at UL's standard for new sprinklers of five pounds per square inch. But UL said the problem was "site-specific."

Test after test of Omegas still produced failure rates of 30 percent to 40 percent, according to the CPSC. But UL continued to call the problem site-specific--suggesting a problem with installation or the sprinkler system itself, not a design flaw. It continued to say that even after the recall and stopped only after the CPSC wrote UL, accusing it of making "several misleading statements" that could discourage participation in the recall.

CAPTION: Debra Rade, UL's chief legal officer, said UL "acted very responsibly" regarding problems with the Omega sprinkler system.