Amazon is facing a suit in a Texas court on behalf of a nationwide class of warehouse workers who claim the company's human resources smartphone app wrongly denied their requests for disability accommodations.

Amazon warehouse employees are required to download an app called A to Z on their smartphones where they can input their request for an accommodation, check their schedules or ask for time off, the suit claims.

But the app routinely turns down requests for disability accommodations and does not engage in the interactive process required under the Americans With Disabilities Act, according to the suit, filed Monday in the Northern District of Texas.