It is not just defects that give rise to failure. Failures can also be caused by environmental conditions as well: for example, a radiation burst, a strong magnetic field, electronic fields, or pollution could cause faults in hardware or firmware. Those faults might prevent or change the execution of software. Failures may also arise because of human error in interacting with the software, perhaps a wrong input value being entered or an output being misinterpreted. Finally, failures may also be caused by someone deliberately trying to cause a failure in a system - malicious damage.