1.   Experts said an air pocket in the letter may have burst, sending invisible spores into the air.

2.   He voiced concern that postal sorting equipment sent spores from anthrax-carrying envelopes into the air.

3.   It lodges in pits and end walls, begins to multiply and forms a colony, which then sends new spores into more vessels.

4.   The anthrax spores were sent in letters addressed primarily to media and political figures.

5.   The envelopes that were used to send anthrax spores through the mail in the fall contained photocopies of letters.

6.   The Hart building closed two months ago after the Daschle letter was opened there, sending anthrax spores into the air.

7.   Technicians were concerned that an electrostatic charge would develop as the envelope was opened, sending anthrax spores flying out of the envelope and losing them to investigators.