When a medical device malfunctions, manufacturers are required to report it to the FDA’s publicly available database. But until 2019, the agency also allowed companies to file private “alternative” summaries of malfunctions. These allowed more than 300,000 reports of breast implant problems to remain hidden since 2009, the FDA acknowledged last year. “This was an approach to be more efficient, and when we recognized that there was a concern, we eliminated it,” says Ashar, adding that the reports are now public.

Tomes of Device Events says she met with the FDA in 2017 to discuss her findings that Allergan had, in some instances, reported problems with devices under the company name “Costa Rica” or “Santa Barbara” (locations where their implants were made), but not under “Allergan.” She shared documents from the meeting with Fortune, saying: “If you’re a physician, you go to the FDA database, and you’re going to look up the name Allergan, not Costa Rica. They were putting off the identification of the problems as long as they could.” (The FDA says it does not comment on individual meetings. The records now include the company name.)

An Allergan spokesperson says the company has “always worked to fully meet all FDA requirements, including our adverse event reporting obligations” and that it currently sends “all adverse event reports to FDA with full and accurate information using the company name and manufacturing location of the implant.”

When the FDA lifted its ban on silicone implants in 2006, it required manufacturers to conduct large, 10 year studies of the women who have their implants. Last year, Mentor and Sientra received “warning letters” from the FDA over their failure to track enough women over time. Both have been allowed to continue selling their products; Ashar says the FDA is “monitoring Mentor and Sientra’s progress” but would not provide specifics. J&J and Sientra both say they are working to increase patient participation in their studies.

A week after Ashar spoke with Fortune for this story, the FDA sent two more warning letters to breast implant manufacturers, citing its “ongoing efforts to protect patients.” One letter, to Allergan, said the company also failed to adequately study the risks of its now-recalled implants once they were on the market. The other letter, to privately-held Ideal Implant, said the company has failed to fix manufacturing and quality-control problems the FDA discovered during an inspection earlier this year. Ideal is also violating requirements for reporting problems with its implants, according to the letter.

The FDA gave both companies 15 working days to respond to its warnings. An Allergan spokesperson said the company is reviewing the letter and “takes this matter seriously.” A spokesperson for Ideal Implant said the company is working closely with the FDA and “strongly supports timely and accurate reporting on product safety.”

The agency is also considering more proactive regulation of future implant sales. In October, the FDA proposed adding a more severe black-box warning label to breast implants, along with an explicit patient-decision checklist. The proposal received more than 1,000 “mostly favorable” public comments, according to Ashar, who adds that “finalizing the guidance is a top priority for the agency.”

“A woman is more likely to be struck by lightning than get this condition,” an Allergan spokeswoman declared. It was January 2011, more than a decade after the first reported case of lymphoma tied to breast implants. The FDA had just issued its first public warning that women with breast implants “may have a very small but increased risk of developing” a disease then called anaplastic large cell lymphoma (ALCL). And in Missouri, Paulette Parr had just gotten her second set of Biocell implants.

At the time, there had been only about 60 cases of ALCL reported worldwide, and manufacturers were quick to downplay the risks. Yet the danger—at least to its bottom line—was grave enough for Allergan to warn investors about the potential negative consequences of the disease, including bad press and financial losses. “The manufacture and sale of breast implant products has been and continues to be the subject of a significant number of product liability claims,” the company warned in March 2011.

The risks of the breast implant business hasn’t dented the company’s prospects as an acquisition target. In 2015, Dublin-based Actavis bought Allergan and assumed its name; four years later, CEO Brent Saunders agreed to sell the combined company to AbbVie, maker of Humira. The $63 billion deal, announced in June 2019 and closed in early May, enables AbbVie to diversify into Botox, breast implants, and the other “medical aesthetics” which, Saunders told CNBC’s Jim Cramer, is “the best business in the biopharmaceuticals space. It’s highly durable, it’s cash pay all over the world, and it’s less regulated, so we don’t have to deal with government payers,” he said.

As Allergan rode the M&A merry-go-round, the chances that a woman with breast implants would be diagnosed with BIA-ALCL climbed from one in 500,000 in 2011 to one in 3,800 in 2019. Peter Cordeiro, a Memorial Sloan Kettering plastic surgeon who followed his patients for 27 years and almost exclusively used Allergan implants, estimates that his patients now have a one in 355 chance of developing the cancer.