A horrifying report from is shedding light on one of the darkest secrets in the : Sexual assaults, a quarter of which are committed by cruise company employees working as crew members.

As a note: the Buzzfeed report includes firsthand descriptions of assault that may be upsetting to some readers. Please read at your own discretion.

The entire report is stomach-churning but well worth your time, especially if you or a loved one takes cruises, but here are the meat and potatoes of the report:

reviewed by BuzzFeed News, cruise ship passengers say they have been dragged into cabins and raped, pushed into janitors’ closets and assaulted, and even attacked in the public corridors of ships. Likewise, parents and guardians have alleged that their children were molested by other passengers or crew members, plied with alcohol, and in some instances, abused by daycare staffers at onboard activity centers. As recently as two weeks ago, the parents of a 17-year-old passenger filed a civil suit alleging she was raped by a fitness instructor onboard a Carnival cruise ship.

In fact, sexual assaults are the most prevalent reported crime on cruise ships, according to the FBI. Since 2015, there have been 454 reported allegations of sex crimes on cruise ships. Experts believe that the actual numbers are far higher, as many sexual assaults often go unreported. (For reference, of all sexual assaults in the US are not reported to law enforcement, according to the Rape, Abuse & Incest National Network.)

And many of the major cruise lines have been told — even by their own security staffers — that more could be done to protect passengers, such as installing more surveillance cameras and hiring additional security personnel. But according to court records, including a deposition from this February in a lawsuit alleging the gang rape of a minor on a Carnival Cruise ship, senior executives have opted not to implement the changes, claiming they’re too expensive.

Troublingly, in many instances, the alleged assailants are the very crew members who are supposed to protect passengers — since 2015 nearly 1 in 4 of all reported sexual assaults on cruise lines have been committed by a crew member, according to a BuzzFeed News analysis of FBI data.

Cruise ships have known about the sexual assault problem for over 20 years, yet continue to do very little to keep travelers safe. When a crime does occur, it’s up to inexperienced security guards to collect forensic data and overstretched FBI agents to investigate. Often evidence is lost, deleted or mishandled. BuzzFeed goes on to back this report up with in-depth interviews, court transcripts and crime data. You can read the whole thing .

Cruises already suck for a whole host of reason. Besides being , they’re incredibly wasteful and polluting — both in and the they dump into the ocean every year.