The Food and Drug Administration needs to do more to solve a shortage of IV saline and other key products during the record-setting flu season, a group of lawmakers said Friday.

The FDA has made several moves to mitigate the shortage caused by Hurricane Maria’s pummeling of Puerto Rico, a key manufacturing center of IV saline. The actions include speeding up imports of saline from overseas and hastening approval of new saline products. However, lawmakers said in a letter to the agency Friday that the moves have not quelled concerns from healthcare providers.