(Rewrites throughout with FBI notice to parcel delivery companies)
By Eric M. Johnson
March 21 (Reuters) - The FBI has reminded parcel delivery companies in the United States to follow "established protocols" for handling suspicious packages following a bomb blast at a FedEx Corp sorting facility in Texas, an agency spokeswoman said on Wednesday.
A three-week bombing spree, which sent a shiver through the Texas capital of Austin and rattled the rest of the country, raised fears about the possibility of other attackers via package delivery.
"In light of the bombings in Austin the FBI has reached out to our private-sector partners to remind them of established protocols of how to handle suspicious packages," Federal Bureau of Investigation spokeswoman Lindsay Ram said by email.
There was no suggestion by the FBI that FedEx had not followed protocols to the letter.
Federal prosecutors said on Wednesday they had charged Mark Conditt of Pflugerville, Texas, with unlawful possession and transfer of a destructive device before he blew himself up as police closed in on his vehicle.
FedEx, United Parcel Service Inc and other couriers collect a vast amount of data on packages in their systems. Some of the information may have helped identify the man who carried out the bombings, a FedEx executive said.
FedEx Chief Operations Officer David Bronczek told employees in an internal memo seen by Reuters that the company provided "key evidence" to law enforcement officials on identifying the suspect.
The FBI's Ram did not elaborate on whether the agency was concerned about other deadly packages that may have slipped into a mail network that handles roughly 40 million parcels daily in the United States.
FedEx was taking the extraordinary step of screening every package at the sorting facility outside Austin where a parcel bomb exploded on a conveyor belt on Tuesday. It was also x-raying entire trailers filled with packages at that location and other trailers with packages originating from central Texas, a FedEx manager said.
FedEx spokesman Jim McCluskey declined to comment on package screening and on the evidence FedEx provided authorities.
Like FedEx, UPS shipping terms and conditions allow employees to open and inspect packages, and the companies train employees on how to respond if they see packages that look suspicious or may contain drugs.
FedEx and UPS have so far not described steps they may take to expand screening.
UPS spokesman Glenn Zaccara said the company constantly evaluates and adjusts its security measures, but does not discuss them in order to maintain their effectiveness.
The United States Postal Service said in a statement that although it appeared none of the devices in Austin were sent through the U.S. mail, USPS reminded employees and customers to be observant about suspicious packages.
Inspectors in its Dangerous Mail Investigations Program "are trained to recognize the common characteristics of suspicious mail and are highly proficient in the use of state-of-the-art equipment to include portable X-ray machines," the USPS said.
The FedEx manager said in-bound international shipments are screened by x-ray or bomb-sniffing dogs, and said the Texas blast could lead to changes in domestic security screening.
Airport-like security measures inside package sorting facilities and retail locations would be a costly and unnecessary step that would paralyze operations, particularly given the rarity of package bombs, said Satish Jindel, a founder of the delivery company that became FedEx Ground.
Reporting by Eric M. Johnson; Additional reporting by Mark Hosenball; Editing by Lisa Shumaker and Grant McCool