A new baby formula warning threatens to strain already stretched supplies even more, leaving desperate parents scrambling in the States. The Food and Drug Administration announced Thursday that it is working with the manufacturer to initiate a voluntary recall of certain powdered infant formula after complaints that four infants fell ill and were hospitalized. One death may possibly be linked to tainted formula. The warning and likely recall only increases availability concerns for parents who for months have found store shelves increasingly bare of formula, as unexpected demand and labor shortages disrupt supplies. Baby formula has been in short supply around the country for months. In November and December, one of the top makers apologized to customers complaining about shortages, saying that "due to high demand" some of its products would be out of stock for an extended period of time. An industry trade group representing top formula makers has cited general supply chain issues affecting all manufacturers, specifically transportation, labor and logistical snarls. The group has said in a statement that infant formula manufacturers are actively working with suppliers, distributors, retailers and state agencies to ensure availability and access to infant formula products. Meanwhile, retailers say that makers are having difficulty sourcing raw ingredients and product supply challenges are currently impacting most of the retail industry. "We're continuing to work with our national brand baby formula vendors to address this issue and we regret any inconvenience that our customers may be experiencing," said a spokesperson from a major chain pharmacy.