The deadliest mass shooting in modern U.S. history is adding to soaring costs for insurance companies, which are already taking a beating this year from an onslaught of hurricanes, earthquakes and wildfires.

The industry may have to shell out more than $1 billion for the Las Vegas massacre, insurance executives say. Acts of a solo gunman, who killed almost 60 people and injured about 500 others when he fired into the crowd of a country music festival last month from his Mandalay Bay hotel room, have resulted in multiple lawsuits. Victims have accused the hotel and its owner, MGM Resorts International, and concert promoter Live Nation Entertainment Inc., of failing to protect people at the event.

The shooting will drive up man-made disaster costs for insurers, after losses for such incidents worldwide totaled $7.8 billion in 2016, according to data from reinsurer Swiss Re. Brokers and lawyers expect claims related to the Las Vegas incident from life and health insurance, and class-action lawsuits, to continue for years.

“It doesn’t take long to get to a large number” in claims, said Heidi Lawson, a lawyer at Mintz Levin who specializes in insurance litigation and investigations. “There was a failure to oversee, a failure to supervise, a failure to set up internal security measures.”

Costly Season

Long-term costs insurers face for incidents like the one in Las Vegas include physical damage, hotel and event planner liability, workers’ compensation and festival refunds, according to Peter Williams, global leader for live events at Allianz SE’s global corporate and specialty unit.

Live Nation declined to comment other than to say the company is fully cooperating with the Federal Bureau of Investigation. MGM expects its insurance to cover liabilities tied to the lawsuits, the company said in a filing earlier this week. Chief Executive Officer James Murren said on a conference call Wednesday that MGM saw a spike in cancellations after the Las Vegas incident and bookings initially declined.

Liabilities from the massacre add to an already costly insurance season. The industry is facing as much as $120 billion from claims related to hurricanes that raked the Southeastern U.S. this quarter, according to catastrophe-modeling firm RMS. Wildfires that struck Northern California in October may cost insurers as much as $10 billion, Imperial Capital credit analyst David Havens said Wednesday in a note to clients.

While insurers have plenty of experience trying to predict those natural disasters, modeling the motives of perpetrators who can single-handedly cause catastrophes is a much greater challenge for the industry, said Nick Beecroft, a former emerging risks manager at Lloyd’s of London.

Terrorism Insurance

The Las Vegas incident was the second for Live Nation to result in mass casualties this year. In May, more than 20 people were killed in a terrorist attack at an Ariana Grande concert in Manchester, U.K.

The U.S. Treasury Department has a terrorism insurance program to help shield insurers from losses, but President Donald Trump and the Department of Homeland Security have not declared the Las Vegas shooting to be an act of terrorism. The Sept. 11, 2001 attacks, the first to be covered by the program, resulted in $43.6 billion of property, life and liability claims. It was the second costliest insurance event after Hurricane Katrina, which totaled $49 billion.

Events like the Vegas tragedy “touch a number of policies, some of which you don’t necessarily see immediately,” Allianz’s Williams said. “It takes time to work out exactly what it’ll really cost.”