Asri-unix.1155
net.space
utzoo!decvax!cca!sri-unix!David.Smith@CMU-10A
Mon Apr  5 09:06:41 1982
What noxious residue?
From: David.Smith at CMU-10A (C410DS30)
The ET carries liquid hydrogen and liquid oxygen.  What is so noxious
about that?

The shuttle orbiter itself does use noxious propellants, in the form
of hydrazine and nitrogen tetroxide for the OMS and attitude control
rockets.  These are carried in the orbiter, not the ET.  They
explain the caution with which ground personnel approach the orbiter
after landing -- from the right direction, clothed in protective
garb, and using a wind machine.