The Lipitor recall continues with Pfizer’s recall of 19,000 additional bottles of the popular cholesterol drug.

A musty smell has led to four recalls, totaling 345,000 bottles recalled since August 2010.

The musty odor comes from TBA, a chemical used to treat the wooden pallets on which the product was stored. Pfizer says the foul-smelling bottles were supplied by a third-party bottle manufacturer, and that the company prohibits use of TBA-treated wood to ship its medicines.

It’s unclear whether TBA can be toxic, and the FDA claims "health risks appear to be minimal."

But some people have reported "gastrointestinal events" because of the foul odor or taste of the drug stored in bottles contaminated with trace amounts of TBA.

TBA in storage pallets is blamed for recent recalls of Johnson & Johnson’s Tylenol.

All of the recalled bottles contain Lipitor 40 milligram tablets. The 19,000 bottles represent a single lot of Lipitor. The lot number of the current recall is 0836050.