QUESTION:
Does the chemical used to heat up the oil in Sojourner pollute Mars?

ANSWER from David Mittman on November 6, 1997:
The rover Sojourner uses three small D-cell-battery-sized RHUs to help keep
itself warm. Most of its heating comes from the use of its electronics
during the day. These RHUs will remain encased within Sojourner's insulated
Warm Electronics Box.

Mars Pathfinder has caused some litter on Mars, though. The heatshield,
backshell and parachute were ejected during entry, descent and landing, and
ended up on the surface of Mars. We believe we've located the backshell in
images taken from the lander.

The rover Sojourner has left over 100 meters worth of tracks on the
otherwise pristine Martian surface. These track marks will remain for many
years to come.