To limit the probability that persons in the vicinity of the site will hit or trip over waste material, which could lead to harm to persons.
To limit the probability that waste or other material will fall onto persons in the vicinity of the site, which could lead to harm to persons.
To limit the probability that unauthorized persons will gain access to the waste material, which could lead to unsafe conditions [e.g. persons tripping on the waste, cutting themselves on sharp objects], which could lead to harm to persons.