Technology to help investigators trace the origin of explosives after bombings such as the one in Oklahoma City was developed more than 15 years ago, but the National Rifle Assn. and others, citing safety concerns, have lobbied successfully over the years to block its implementation.
This week, President Clinton proposed using so-called "taggants" to trace bomb-making material as part of his broad package of counterterrorism proposals.
Once again, it appears the issue may not be settled without a difficult battle.
On one side stand federal law enforcement authorities who say that adequate technology has long been available to place indestructible microscopic chips into dynamite, gun powder and other explosives so they can be traced back to the manufacturer, wholesaler and even the customer who bought the product.
Opposing the measure are some manufacturing groups, including the Institute of Makers of Explosives. They question the safety, cost and effectiveness of taggants, particularly in bombs made with ammonium nitrate, a key ingredient in the Oklahoma City blast.
An NRA spokesman declined to answer questions Thursday. In the past, the group has consistently opposed taggants in gun powder, contending they could affect the trajectory of bullets and also amount to a de facto form of federal weapons registration.
The debate over taggants first arose in the late 1970s, when the Treasury Department and other government agencies pushed for legislation to require taggants in all explosives manufactured within the United States.
The impetus was a series of five major bombings in the United States, including two in New York City in 1975. One bomb hidden in a locker in La Guardia Airport killed 11 people and injured 75; another explosion at a historic tavern in the city killed four people.
Among those who argued at the time that taggants could prove a valuable tool was Alcohol, Tobacco and Firearms special agent Larry Cornelison, who served on a team that tested and promoted the microscopic materials.
Cornelison, now an ATF supervisor in Los Angeles, says that if it weren't for opposition from gun and explosives lobbyists, taggants could have been used to help solve not only the April 19 bombing in Oklahoma City but also the long-unsolved Unabomber serial attacks, the World Trade Center car bombing and a host of other cases.
"I can think of any number of incidents where we had bombings . . . where it could have been very beneficial," Cornelison said Thursday. "In Oklahoma City, there would have been a good investigative lead--it would have been very valuable to know just where this explosive material came from."
The legislative momentum diminished in 1980 upon release of a report by congressional researchers. The Office of Technology Assessment study showed that taggants could increase arrests related to bombings by as much as 75%. But it also suggested additional safety tests before requiring taggants in all explosives.
ATF agents countered that the technology was safe. But lobbying groups including the NRA, which had pushed to exempt black and smokeless powders from the list of explosives to be tagged, won the day, prevailing by a single vote before a Senate committee.
More recently, the issue failed to even come to a vote following its initial inclusion in a domestic anti-terrorism bill introduced by Rep. Charles E. Schumer (D-N.Y.) after the 1993 trade center bombing.
Clinton, in his initiative this week, called for passage of legislation to require that, within one year, taggants be included in the raw materials used in standard explosive devices. Clinton also asked for congressional permission for ATF to study and report on new technologies that would help detect concealed explosives.
At a White House press briefing Wednesday, Deputy Atty. Gen. Jamie Gorelick said the ATF should investigate whether "you could put taggants in something like a fertilizer, or whether you could render it inert in some way."
Ronald K. Noble, undersecretary of the Treasury Department, added that in the Oklahoma bombing, taggants in the ingredients used to detonate the ammonium nitrate could have been traced and detected.
Noble also said that the Administration is currently focusing on the use of taggants in explosives rather than in gunpowder. In the late 1970s, when the NRA sought to exempt gunpowder, Treasury officials said it was important to include it because gunpowder was often used by terrorist bombers.
The Institute of Makers of Explosives issued a strong statement Thursday opposing any requirement that microscopic chips be placed in explosives.
The prepared statement declared that taggants would present a safety problem "during the manufacture of the explosive and during the use of the explosive by miners, quarry companies and construction companies."
The problem, the IME said, is that the chips can affect the stability of explosives, exposing workers to safety perils.
Times staff writer Eric Lichtblau contributed to this story.