Inhospitable

[Dave Paprocki]

Not hospitable; not disposed to show hospitality to
strangers or guests; as, an inhospitable person or people.

[Little_Girl]

This means when something is so [hazardous] and [poisonous] that no human being can [survive]. Fortunately, they will die instantly!

[Tina]

(of an environment) harsh and difficult to live in.