These fire debris bags are made from nylon 11 (similar to Rilsan). A characteristic of nylon 11 is that apolar compounds diffuse through it only at low rates. Apolar compounds include, for example, the hydrocarbons that make up gasoline and paint thinner.
 
These bags are therefore particularly suited for transportation of samples of fire debris that need to be analyzed for the presence of fire accelerants.
 
Sealing of the bags is done by twisting the opening of the bag, folding it over and then using a tiewrap to keep everything in place.