New Crop-Dusting Restrictions Weighed

Faced with mounting evidence that terrorists had shown unusual interest in agricultural planes, federal officials are considering new restrictions on the export of crop-dusting and other aerosol equipment that could be used in chemical or biological weapons.

The proposal comes as law enforcement officials are reviewing the threat that crop-dusters, which are designed to spray pesticides and fertilizers on crops, could be used to deliver far more ominous materials.

In Florida, a mechanic at a crop-dusting service said Monday that Mohamed Atta, suspected of piloting a plane into the World Trade Center in the Sept. 11 terror attacks, was among several foreign men who had visited his airport earlier this year and asked detailed questions about crop-dusting aircraft.

A Florida bank president said that a man, possibly Atta, had approached his bank with an unusual request for a loan to buy a crop-duster after making a similar request of the U.S. Department of Agriculture last year.

In Washington, Atty. Gen. John Ashcroft said authorities found “a significant amount” of crop-dusting information downloaded from the Internet when they searched the computer and personal baggage of a man they are holding for questioning.

The FBI has asked local law enforcement officials to identify crop-dusting aircraft in their areas and to “ensure that they are secured,” Ashcroft told the House Judiciary Committee. Federal aviation officials have grounded crop-dusters twice since Sept. 11, in addition to the general grounding of all aircraft immediately after the attack. The latest grounding order, which was issued Sunday and ended early today, had been requested by federal law enforcement officials.

“The FBI assesses the uses of this type of aircraft to distribute chemical or biological weapons of mass destruction as potential threats to Americans,” Ashcroft said. He said the FBI had received information “indicating the possibility of attacks” using crop-dusting aircraft, but that the agency had no specific information about any such attack.

But some terrorism and industry experts said Monday that the potential for crop-dusting planes to spread anthrax, smallpox, nerve gas or some other toxic material is low. The planes, they said, are poorly equipped to handle such a task.

Pilots Say Specialized Training Necessary

“The possibility that some terrorist organization would secure that much lethal agent, and be able to load it into a crop-duster without killing themselves and killing the pilot, is a very distant possibility,” said Raymond Zilinskas, an expert in biological weapons at the Monterey Institute of International Studies.

Crop-dusting operators said that flying their planes requires specialized knowledge. Where most private planes have a single wheel under the nose, agricultural planes have a wheel under the tail, meant to stabilize the plane as it carries heavy loads over rough runways.

“Without having specialized training, I doubt someone could get it off the ground without tearing it up first,” said Mark Hartz of Grand Prairie Dusters Inc. in Almyra, Ark.

Moreover, the tanks on crop-dusters have vents, making them poor containers for a chemical agent such as nerve gas, said Patrick Kornegay, who runs a Texas crop-dusting company and is president of the National Agricultural Aviation Assn. “You can’t pump gas through the nozzle system,” he said. “It would flow out of the vents.”

Zilinskas, who served on two United Nations teams that inspected possible biological weapons sites in Iraq, said there are a range of technical problems to overcome in creating a biological or chemical weapon, but that Iraq and other hostile nations were working to solve them.

Zilinskas said that obtaining virulent strains of biological materials is difficult, and so is finding a way to grow them in suspension while keeping them potent and alive.

Equally difficult is creating a nozzle to disperse the materials, he said. Crop-dusting chemicals tend to be sprayed in large droplets, because farmers want the pesticides to fall onto plants quickly and sometimes to pierce the upper canopy of crop leaves. If the same nozzle sprayed a biological agent, Zilinskas said, the material would also fall to the ground and would not be inhaled.

If people did inhale the drops, he said, they would land in the upper respiratory system and would likely be coughed out.

But if the nozzle holes are too small, Zilinskas said, the lethal bacteria or viruses would be damaged and rendered impotent as they pass through. Moreover, he said, the materials would quickly clog up the nozzle.

Interest in Planes Alarms Some Experts

Two of these technical hurdles stopped the Japanese cult Aum Shinrikyo when it tried to spray Tokyo residents with anthrax in the early 1990s, Zilinskas said. “Not only did they have a problem obtaining a virulent strain--in fact, they obtained a nonvirulent strain--but when they drove their trucks through the city, the testimony is that their nozzles got clogged up,” he said.

Aum Shinrikyo later killed 13 people and sickened hundreds by releasing the nerve gas sarin in the Tokyo subway system. But Zilinskas called it “a remote possibility” that terrorists could import or create enough nerve gas to cause mass casualties or mount the tanks on a crop-duster.

Other experts were more alarmed by the news of terrorist interest in crop-dusters. Crop-dusting nozzles “wouldn’t be as effective as other hardware, but, sure, it would be something to be concerned about,” said Ivan Kirk, a crop-dusting specialist with the U.S. Department of Agriculture in College Station, Texas.

Kirk noted that some airborne spraying is aimed not at crops but at mosquitoes or medflies. That equipment uses a finer nozzle that aims to keep the pesticide in the air for a longer period of time, he said.

The proposed restriction on aerosol equipment exports is aimed at these finer nozzles, with orifices of 15 microns or smaller, Kirk said. Crop-duster nozzles often have orifices of 200 microns to 350 microns.

According to a document obtained by the National Agricultural Aviation Assn., State Department weapons proliferation officials have proposed that exports of certain “aircraft sprayers” and other aerosol equipment require a license if sent to a limited set of countries. State Department officials are citing “anti-terrorist reasons” for the proposed requirement, the document says. It is aimed at preventing the equipment from reaching Syria, Iran, Iraq, North Korea, Sudan, Cuba and Libya.

At the State Department, an official could provide few details of the proposal, but said it arose after the Sept. 11 terrorist attacks. State Department officials discussed the idea Monday with officials at the Commerce Department, which oversees export restrictions.

Bank Officer Recalls Unusual Loan Request

The Florida bank president said Monday that one of his loan officers remembered getting a request by telephone for financing to buy a crop-duster or crop-dusting company. Robert Epling, president of Community Bank of Florida in Homestead, said the officer could not identify the caller as Atta, and that the caller never submitted a loan application.

But Epling said the loan officer remembered the call because there is little crop-dusting in the area, and few requests to finance that business.

Epling said the loan officer recalled the incident after the FBI asked his bank last week to search its records for any signs of contact with Atta, particularly in connection with crop-dusting. The FBI also said that Atta had approached an area branch of the U.S. Department of Agriculture, in person, for a loan. Epling said his bank shared a building with a branch office of the Agriculture Department.

In Belle Glade, Fla., on Monday, a worker at South Florida Crop Care, a crop-dusting service, recalled two visits by three foreign men earlier this year.

During one visit, one man asked numerous questions about the capabilities of crop-dusting aircraft. “He wanted to know how far the plane would fly, how much fuel the plane holds, what the capacity and the weight of the airplane were,” said James Lester, in charge of ground maintenance for South Florida Crop Care. The man even wanted to get into the cockpit, but Lester refused.

Wednesday, Lester was shown a book of photographs by the FBI, and identified the inquisitive visitor as Atta, a presumed leader of the Sept. 11 suicide attacks.

Atta returned for a second visit to the Belle Glade airport sometime between March and May, Lester said.

J.D. “Willie” Lee, general manager of South Florida Crop Care, told reporters that groups of two or three Middle Eastern men came by almost every weekend for six or eight weeks before the terrorist attacks.

“The bottom line is, we were not observant at the time,” Lee said. “To other people who handle hazardous products or equipment at any time, I say, be observant and try to get some background on suspicious people.”

*

Zitner reported from Washington and Dahlburg from Florida. Times staff writer Norman Kempster also contributed to this report.