To make the poison gas phosgene requires a "gas mask" consisting of water to hydrolise any gas that escapes make the water alkali and it workes even better. Scuba diving kit would be more than adequate. The person that made the gas in the first place with no protection died something like 2 days later.

If you condense on ice (even better dry - ice bought, or make using a fire extinguisher), you've got a liquid. Place in a thermos and it'll stay that way for at least a few hours.

Yes, the makers might die later. so what? chances are they'll get the gas to target before that.

Experts require the protection so that 100% of the poison doesn't get through. Protecting against 99% is a lot easier and does the job. Serious terrorists are not concerned with 10% lung fibrosis. Workers doing a job are.

I've no knowledge about binary liquids, but quarries routinely use liquid explosives.

Go work in a quarry. Nick some material from it. Make a simple detonator for it - or better yet pinch one from the quarry. Get on Bristol Airport late at night when security is low at best. Boom.

Terror does mean that the government gets its usual farces out of the public mind. And saying that something was prevented but it is hush-hush means that the masses nod understandingly and put up with anything.

Very good point about the white powder though. Two packets of "sugar" could probably down a plane.