containment practices are genetic manipulations or choices of 
conditions for the experiment which serve to eliminate or 
minimize the possibility of biologically meaningful release of 
experimental organisms. She noted that biological containment 
practices are in most cases as effective , or more effective, than 
the physical containment practices. 
Dr. Fedoroff said organisms had been divided for administrative 
purposes: those whose use would require only notification of the 
IBC , and those requiring prior review and approval. She noted 
that the classification of these was summarized in tab 1292. 
Also, the open box containment was appropriate for essentially 
all experiments involving plants, plant-associated micro- 
organisms, and plant-associated small animals including nema- 
todes. However, "exotic microorganisms" which are defined as 
those that do not exist in this country and are clearly serious 
pathogens in their countries of origin would be contained in a 
closed box. 
Dr. Fedoroff said a containment system was set up along the lines 
of the biosafety levels for microorganisms but that the suffix 
"P" would be used to connote plants. Therefore, there would be 
BLl-P , BL2-P, BL3-P, and BL4-P levels of containment. 
BL1-P containment would be for experiments in which the plants 
were non-exotic, innocuous to the ecosystems outside, and where 
small animals are not involved or can be controlled. BL2-P would 
have screens added over the windows to protect not only the 
outside from the inside but also the inside from the outside and 
is relevant when insect vectors are involved. BL3-P and BL4-P are 
both closed boxes with the difference being in the stringency of 
filtration of what goes in and out of the facility and how well 
it is isolated from the surrounding area. Dr. Fedoroff noted 
that she was unclear as to whether the BL4-P was necessary for 
any organism but that a short list of organisms requiring this 
level of containment does exist. 
As far as biological containment principles. Dr. Fedoroff noted 
that these were different procedures to limit dissemination of 
plants, the microorganisms associated with them, and the small 
animals associated with them. There are some simple procedures 
such as covering reproductive structures and collecting seeds, 
using male sterile plants, or ensuring no plants that can cross- 
fertilize are within the distance that pollen can disperse. Other 
procedures may include working with a serious plant pathogen that 
is extremely contagious and associated with a plant in the 
winter. Microorganisms can be injected and attenuated strains 
can be used. A very important biological control is carrying out 
experiments in the absence of any vector required for 
transmission. Another choice could be to use microorganisms that 
have an obligate association with the plant. Furthermore, 
microorganisms that are genetically disabled to minimize survival 
[70] 
Recombinant DNA Research, Volume 13 
