To limit the probability that ammonium nitrate will come into contact with incompatible materials, which could lead to the decomposition of the ammonium nitrate, which could lead to the ammonium nitrate becoming unstable or reactive, which could lead to a fire or explosion, which could lead to harm to persons.
To limit the probability that ammonium nitrate will come into contact with ignition sources [e.g. hot parts] from parked industrial trucks, which could lead to a fire or explosion involving the ammonium nitrate, which could lead to harm to persons.