In India, people of the Valmiki caste are effectively forced to clean toilets and septic tanks, because the caste bigotry won't let them do anything else.

Rather than doing the job the safe and clean way that it's done elsewhere, they are forced to do it by hand without safety gear. That makes the work dangerous.

Without the bigotry, the job would have to be done by someone, but it could be done safely. A society without caste bigotry might invest in plumbing to make parts of the job unnecessary.