There's been a lot of questioning lately regarding just why it was necessary to intercept the USA 193 spy satellite. The first reason given was the hydrazine (jet fuel) onboard. However, NPR's Pentagon correspondent Tom Bowman was asked how dangerous it actually was, saying

"Well, [it's] not very dangerous. They said you would have to stand over it and breathe it for quite some time to really have a problem with it."

That sounds like it deserves a redneck joke

Dwayne: Susie May, were's dat' husband'a yours?
Susie May: Oh! Donny done found hisself a big ole' tank'a sumpin' call hy-drow-zeen,. Says it smayulls reeeeal good. He lawcked hisself in tha' bathroom all afta'noon jussa' smellin' his hy-drow-zeen.
Dwayne: Goodness me, Susie May! Don't y'all know dat' sniffin' hy-drow-zeen can cause irritation of the eyes, nose, an' throat, dizziness, headache, nausea, pulmonary edema, seizures, and coma?
Susia May: Naw. Day-um. [Sighs and turns her head, yelling into trailer] ]Donny! 'less you want pulmonary edema, you bess queet sniffin' dat' sweet tank you foun' in tha' creek!

Back at NPR, Tom Bowman went on to say, "The health concern was pretty minimal." Bowman also differentiated the US' recent interception from China's destruction of a weather satellite over a year ago. The Chinese satellite was much higher than the USA 193, for example. Bowman supposes that the reasons for the US' move was to make sure the spy technology on board wouldn't get into the hands of folks we don't trust, as he suggested in another NPR story about the mission:

Government officials say they are concerned that the fuel tank could land in a populated area, rupture and turn into a toxic gas. The fuel is hydrazine — which in gas form would be similar to chlorine and could damage skin and lungs. Some experts doubt this rationale, however. John Pike with globalsecurity.org believes American officials worry that pieces of this spy satellite (which takes pictures) could fall into the hands of the Chinese or Russians, who could learn more about how the United States builds these satellites.

In an article yesterday about why the missile interception would be a bad idea, space and research analyst Jeffrey Mason said [emphasis mine]

Of course there is the possibility that the planned justification for shooting down the spy satellite--to destroy the hydrazine fuel and protect the populace below--is a cover for the actual rationale for launching the mission: to ensure that no resulting debris from the billion dollar satellite can be recovered and studied by other nations. Surely a military that prides itself on its development of a global strike capability ought to be able to effectively track and monitor this debris while publicly announcing that our government considers recovery of any de-orbited material as an act of espionage (combined with a promise of monetary reward for any government or individual that returns the material to the closest American embassy within 24 hours of its retrieval).

There's something interesting here. If the US did decide to shoot the satellite down because of the sophisticated spy technology onboard, doesn't that beg a very simple question: if it's so sophisticated, can they not track the satellite? In the highly unlikely event that the satellite touches down on land, wouldn't we be able to go snatch it up? If it plunges into the ocean, can't we track it and scoop it out?

Alas, despite those saying the interception wasn't necessary, the satellite was intercepted by the first-ever ship based missile to carry out such a mission.