"There are laws in 13 states that prohibit any organization from covering the tax on any product, and CVS is working through operational matters in Arizona and hope to be able to cover the tax in the future," a CVS spokesperson said in an email.CVS is also working with other organizations to eliminate menstrual taxes altogether, according to the company, which operates 9,900 retail outlets in all 50 states, the District of Columbia and Puerto Rico."We believe that no material basic necessity, including period supplies and/or diapers, should be subject to state sales taxes," Joanne Samuel Goldblum, CEO of the groups, told CBS MoneyWatch in an emailed statement.The concept of imposing a sales tax on products that half the population needs for a significant part of their lives has been under fire in some quarters for decades, with 21 states currently engaged in the practice, according to USA Facts.At the same time, 15 states exempted period products from sales tax: California, Connecticut, Florida, Illinois, Maryland, Massachusetts, Minnesota, Nevada, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Utah and Washington."