The Camden Yards escalator that injured 44 fans when it malfunctioned last month often carried more weight than its state-approved capacity, based on a comparison of inspection records and fans' accounts.
State records show that the first-base side escalator, which stretches from the ground-level concourse to the upper deck, is approved to carry up to 80 people -- or 16,000 pounds.
But several victims of the June 18 accident say that more than 150 people were aboard the escalator when it stopped moving up, reversed direction and sent frightened fans on a free fall. That would represent a load of about 22,500 pounds, using the industry's estimated average passenger weight.
And a half-dozen fans said in interviews that the 55-foot-high escalator -- the closest to stadium parking lots -- often was jammed. "Sometimes it's elbow to elbow, all the way up, from top to bottom," said Thomas Marr Jr., who has a 13-game ticket package.
Roy Sommerhof, the Orioles' director of stadium operations, did not dispute that the escalator often was crowded. But he declined to comment on the specific number of riders.
Mr. Sommerhof said only that Orioles workers, stationed at the escalator, were instructed to limit ridership to two fans on each of the escalator's 80 steps. That could result in a load of as many as 160 people.
The accident, which occurred half an hour before an Orioles game with the Minnesota Twins, was caused by a broken metal shaft, according to the Maryland Stadium Authority. But investigators still haven't determined why the shaft sheared near each of the two gear wheels that help to turn the escalator.
Operating an escalator over its capacity can be dangerous if the brakes are not properly maintained, industry experts say. Colorado-based consultant Carl J. White, a leading escalator safety analyst, said overcrowding can cause an escalator to stop and can lead to a "runaway" if the brakes fail.
"In the up direction, a runaway condition would be that the brake would fail to hold the load and the escalator would reverse at an increasing speed until enough people were thrown off the escalator so that the brake would hold the remaining load," he said.
Neither he nor others familiar with the Camden Yards investigation, though, could say conclusively that excessive weight caused the accident.
The escalator, the longest of five at the ballpark, remains out of service while a San Antonio laboratory examines parts damaged in the accident. It might not reopen this season.
A spokesman for Montgomery Elevator Co., the Moline, Ill.-based manufacturer, said the escalator "holds the required loads."
Timothy L. Duin, vice president of risk management at Montgomery, said he did not know the capacity of the Camden Yards escalator, but said he was certain that it met national standards. He said he was not familiar with weight limits on Maryland inspection records.
Joseph E. Foss, the Orioles' vice chairman for business operations, said he is not aware of the team being told of weight restrictions. The team would slow the crowd flow on escalators if necessary, to comply with state and national standards, he added.
Safety inspection records from the state Department of Licensing and Regulation's Labor and Industry Division show that the escalator was approved in 1992 to carry 80 passengers at a time.
But on the night of the accident, the escalator's 40-inch wide steps were jammed, some fans say.
"That escalator was packed. . . . There was a long line from different places sort of merging just to get on the escalator. There were no spaces in-between," said Fern Aefsky, 38, a New York resident who was at the game to celebrate the completion of her doctoral studies at the University of Maryland.
Syd Manekofsky, 72, of Silver Spring, who has a 13-game ticket package, also said the escalator was full when the accident occurred.
"It was fully packed as it usually is. Probably at least two or three people on each step," said Mr. Manekofsky, adding that he sustained "aches and pains" to his rib area, back and neck.
He said employees at the stadium try to pace fans, but that the fans usually push through and crowd the escalator.
Sean Greenman, 16, of Ellicott City, another 13-game ticket package holder, agreed. "A lot of times I've been there, an usher would space people. On [June 18], it was nonstop."
He said he was nearly three-quarters of the way up the escalator when it stopped and plunged -- falling until the step he was on landed seven to 10 steps from the bottom. He said he suffered a gash on his right heel and that a friend was cut on the leg.
Twenty-seven of the 44 people injured in the accident were sent to hospitals for treatment of cuts, bruises, broken bones and other injuries. The parents of an injured Ellicott City teen-ager have filed a lawsuit against the escalator manufacturer.
Other Orioles fans say that a crowded escalator is not unusual at the stadium, as eager fans rush toward their seats.
Mr. Marr, whose father was an Orioles announcer, said the large, first-base side escalator often has been jammed while a smaller escalator leading to the pricey club level was lightly used.
He complained that ushers do not allow upper level ticket-holders to use the club-level escalator for a ride halfway to their destination. That forces more passengers onto the large escalator, he said.
Season-ticket holder Heather Supik, 27, said sometimes there are spaces on the large escalator, particularly when ushers regulate crowd flow. At other times, she said, people pack that escalator.
Edward E. Cline, deputy director of the stadium authority, said a mathematical formula contained in material from Montgomery Elevator rates the escalator's capacity at about 146 passengers. The company has never warned stadium officials to limit the number, he added.
He said Montgomery Elevator has assured authority officials that it was "impossible to exceed the weight limits . . . even if you put three people on each step." He also insisted that it is difficult to fully pack an escalator because passengers tend to leave a space between riders ahead of them.
The escalator held 26,000 pounds of steel bars during an alignment test before the baseball season began this year, Mr. Cline said. The test was performed when the escalator was not moving, he said.
"Somehow, more stress was being put on [the shaft] than it was designed to handle," said Michael T. Shiflet, an escalator safety consultant. Last month, he was contacted about a potential contract by a company that the Orioles had hired for the investigation, but did not get the job. He often is hired to assess such accidents, but is not involved in this investigation.
Mr. Shiflet cited potential reasons for the broken shaft and runaway.
"I would have to say there's either a defect in the device or it wasn't properly engineered," said Mr. Shiflet, owner of DelMarva Inspection Agency of East New Market. "If it was properly engineered to withstand the weight, there was a maintenance problem."
The escalator parts are being examined by the Southwest Research Institute of San Antonio, which was hired by the stadium authority -- with the agreement of Montgomery Elevator.
The industry is proud of its safety record. Although there are thousands of escalator accidents each year, industry officials say, the numbers are small compared with the billions of passenger trips annually.