One recent emailer told me about a bank that backed out of a hiring offer to a customer service representative because it didn’t want to spend $500 on software that would accommodate his blindness.

Discrimination against persons with disabilities is a perennial topic in the workplace. I’ve also heard about a job posting for an accounting manager that required the employee to occasionally lift up to 50 pounds and routinely move or lift 25 pounds. A separate posting, for a university professor’s position, required the ability to lift or move up to 15 pounds.

Job hunters want to know: What do those physical requirements have to do with the basic functions of the job? And what about employers’ responsibilities to provide reasonable accommodation if the worker requires that accommodation to perform the essential functions of the job?

Advocates for people with disabilities tell me that, no matter how small the cost, most employers will opt to avoid job candidates who clearly require accommodation. It’s not that they’re oblivious to the applicant’s desire to work. It’s that they haven’t had experience in providing accommodations or they fear the cost or they worry about taking a chance on the hire.

Employers say that listing physical requirements in job ads helps protect them down the road. It helps weed out candidates who can’t or won’t do things that the employers know are part of the job. Especially in small companies, many jobs have wide-ranging duties.

An accountant may have to move file boxes in the warehouse. A professor may need to carry a stack of textbooks. Even in big companies, a cashier’s job may require wheeling in shopping carts from the parking lot. A recent news item told of a budget-strapped school district that may require its bus drivers to double as janitors.

There are some things an employer can’t demand, according to the law. Hirers can’t legally post a job that says “men only” or “whites only” or clearly discriminate against any legally protected category. But it is legal to post physical requirements that accurately describe the job’s required duties.

Here’s a real example for an accounting job: “While performing the duties of this job, the employee is regularly required to walk, talk, see and hear. The general level of physical activity would be defined as sedentary. The employee is occasionally required to stand and frequently required to sit; use hands to finger, handle, or feel; reach with hands and arms. Some movements of the hands, arms and wrist may involve repetitive motions. Specific vision abilities required by this include close vision, distance vision, color vision, depth perception and ability to adjust focus.”

The onus, then, is on the employer to provide the accommodation that helps a qualified employee surmount a physical barrier to perform those essential functions. But that does take us back to square one, where disability discrimination complaints arise.