State officials yesterday suspended excavation of the Metro extension to Johns Hopkins Hospital because the tunneling may be causing gasoline fumes to leak into homes and businesses.
Since late January, the city Health Department has been fielding complaints about gasoline fumes in the basements of buildings in a six-block area around East Baltimore Street and Broadway in Washington Hill.
That's only two blocks south of where workers are excavating the two new Metro tunnels 40 to 60 feet underground. The tunnels currently stretch about 1,000 feet from Johns Hopkins Hospital to Bond and East Baltimore streets.
Mass Transit Administration officials said it's "likely" that compressed air is leaking from the tunnels and somehow forcing gasoline, left behind in the soil years ago by leaking underground tanks, to migrate horizontally.
"We don't think it's a health or safety threat to the community, but obviously it's quite bothersome," said Peter J. Schmidt, the MTA's assistant general manager for development. "Some residents have reported headaches and things like that."
Betty Hyatt, executive director of the Citizens for Washington Hill, said the fumes have given her a constant low-grade headache and dry nasal passages. Some days, she said, her home smells like gasoline and on other days like nail polish remover.
"In some people's apartments, the odors are so strong they bring tears to your eyes," Mrs. Hyatt said. "When I enter my home, no matter what time of day, I can smell it. It's annoying."
At the Broadway Pharmacy, 1645 E. Baltimore St., gasoline fumes could be detected in the basement storage room "off and on" for at least a month, Larry Roark, a clerk, said yesterday.
A representative of Church Home & Hospital, Broadway and Fayette Street, said there have been "minor" problems with gas fumes in the basements of buildings. A Baltimore Street resident who asked not to be identified said the fumes have caused him to "wake up in the middle of the night with sore throats."
Reuben Dagold, the Health Department's director of community and industrial hygiene, said technicians have found evidence of hydrocarbons in storm water drains and homes, but at no concentrations higher than 77 parts per million.
In comparison, the federal Occupational Safety and Health Administration limits to 300 parts per million on-the-job exposure to airborne hydrocarbons.
Investigators say the source of the gasoline may be the ground water beneath what is now a Popeye's fast-food restaurant at Broadway and Orleans Street, a site formerly occupied by a Shell gasoline station.
"There's likely some tie-in," said Bernard Bigham, acting administrator of the state Department of Environment's underground storage tank program. "It's probably a diffuse source, and since it's an old industrial area, maybe 40, 60 or 80 years old."
This is not the first time the $321 million, 1.5-mile subway extension from Charles Center has experienced problems with gasoline leaks. Tunneling had to be delayed 10 months when crews ran into gasoline-soaked sand and experienced some machinery problems in late 1990, resuming their work last September.
That added $20 million to the cost of construction, in part because the MTA was forced to make the tunnel explosion-proof.
To deal with this most recent setback, the MTA has instructed its tunneling contractor, Kiewit-Shea A.J.V., to do a better job of sealing the tunnels during the halt in excavation, which is expected to last one to two weeks.
In addition, workers will be drilling holes in the ground at points along Broadway this weekend to see if they can intercept the gasoline. One possibility is that the fumes are running along the path of underground utility lines.
MTA officials are scheduled to discuss the problem further with local residents at a meeting of Citizens for Washington Hill at 7 p.m. next Tuesday in the auditorium at Church Hospital.