Many of the approximately 200 wells in the Fallston area tested for a gasoline additive will be retested, officials said yesterday after residents questioned the reliability of an earlier sampling paid for by Exxon Mobil Corp.
Dr. Andrew Bernstein, Harford County's health officer, said the second round of testing - which might begin as early as next week - could help identify the source or sources of methyl- tertiary butyl ether, or MTBE, which has been detected in drinking water from 77 wells in the Upper Crossroads area. Most of the well tests yielded traces of the chemical, though eight registered levels above the state's action level.
"The more information you have the more accurate your conclusions will be," said Bernstein, whose office is helping the state Department of the Environment investigate what is shaping up to be the worst MTBE contamination episode in Maryland.
Officials acknowledge that they have found traces of MTBE more than a half-mile from the Crossroads Exxon at Routes 152 and 165, a suspected source of the contamination. About 40 homes have been tested outside of the half-mile circle initially drawn around the station to check for tainted wells, said Richard McIntire, a spokesman for the state environment department.
In other developments:
Exxon Mobil confirmed that it has begun installing equipment to pump and treat MTBE-contaminated ground water from beneath the Crossroads Exxon station, which it owns. Company spokeswoman Patty E. Delaney reaffirmed that tests have found no leaks in the station's underground storage tanks or fuel lines.
State and local officials said they are investigating other possible sources of MTBE contamination, including at least three other businesses in the neighborhood that once sold gasoline. Two have since closed or changed hands.
Lawyers in the firm of Peter G. Angelos said they have opened an investigation. Angelos's firm has specialized in filing class action lawsuits over exposure to asbestos, lead paint and tobacco smoke.
MTBE has been added to gasoline since the late 1970s to help it burn more cleanly. It is widely credited with helping to reduce air pollution. But the chemical dissolves easily in water and has tainted wells nationwide.
The U.S. Environmental Protection Agency classifies MTBE as a potential human carcinogen based on tests in which laboratory rats and mice inhaled it. Although there is little scientific evidence of health effects in humans, officials say they do not think it poses a risk when consumed at the low levels generally found in drinking water.
The state acts when levels exceed 20 parts per billion because that is the lower limit at which it can be smelled or tasted, rendering water undesirable to drink.
Harford County's health officer acknowledged yesterday that residents' complaints about the well testing that has been done were at least partly behind officials' decision to retest.
"The methodologies that were utilized were not as tight as I guess everybody would have liked," Bernstein said. In one case, a resident said a technician took water from a garden hose on the far side of the house from the well. The EPA specifies that water be sampled from the tap or spigot nearest the well.
Officials said they also decided to expand the range of testing to appease residents upset about not being tested when their neighbors were.
"How would you feel if you were left out?" McIntire said. But he noted that if a well does not have an MTBE reading above the action level, "that's going to be it; there won't be any additional sampling."
Among the Fallston area residents whose well was tested was Kendl P. Philbrick, state secretary of the environment. McIntire said no trace of MTBE was found at Philbrick's home, which is less than a half-mile from the Exxon station.
Loraine Astarita, who is house-sitting for her son, Rick, and his wife, Patsy, on Sheffield Court in Haddon Hurst. said their well tested positive for MTBE.
"My son and daughter-in-law are very upset over this whole situation," she said. "They have a year-old baby in the house. The whole neighborhood is upset."
Exxon Mobil has provided carbon water-filtration systems to 30 homes and businesses and plans to provide treatment for 45 other wells, McIntire said.
Meanwhile, McIntire said, state officials are following up "anecdotal information and tips" about other businesses that reportedly sold gasoline in the vicinity in the past.
Rick Hicks, who operates Crossroads Exxon, said he recalled two stores and a garage nearby that had gasoline pumps when he opened his station 17 years ago. Officials could not confirm or provide any details about those establishments.
Some residents apparently are not content to wait for the state and county to finish their investigation. Lawyers in the firm of Angelos, majority owner of the Baltimore Orioles, have hired experts and begun making inquiries into the problem in Fallston, with an eye to filing a lawsuit because of the contamination.
Sun staff writer Ted Shelsby contributed to this article.