On 17 November 2023, Brazilian student Ana Clara Benevides Machado died from a cardiac arrest at a concert of the Eras Tour by the American singer-songwriter Taylor Swift at Estádio Olímpico Nilton Santos, Rio de Janeiro, amidst a heat wave and a venue ban on personal water bottles.

[note 1] A criminal investigation was opened to determine an official cause of death and a consumer inquiry was launched on the event organizer T4F, a Brazilian entertainment company.

T4F reportedly prohibited concertgoers from bringing their own food and water into the venue, citing "security concerns", which caused about one thousand dehydrated attendees to faint before and during the show.

Many Swifties claimed that the water bottle ban, exacerbated by the heat wave and the stadium's closed vents, caused attendees to fall sick and led to Benevides' death.

Politicians such as the federal minister of justice and public security, Flávio Dino, and the mayor of Rio de Janeiro, Eduardo Paes, announced that precautions would be implemented at future events, with free water stations amongst other obligations.

On 22 November 2023, the government of Brazil passed a federal ordinance mandating free and easily accessible water stations at events henceforth.

In March 2024, NBC News reported that around 100 municipal and state legislatures in Brazil have enshrined mandatory water access at large-scale events into law, attributing it to the "Taylor Swift effect".

A well-known entertainment company in Latin America, T4F was once considered one of the top tour promoters by American music industry magazine Billboard.

T4F mainly offers services for event promotion, operations of box office and venue, and food, beverage and merchandise sales amongst others, according to its official website.

[5] On 20 June, congress members of Brazil filed the "Taylor Swift Law", which penalized scalpers with up to four years in prison and a fine of up to 100 times the value of the ticket.

"[17] Others stated that the venue closed its vents, which used to be open, to prevent outsiders from viewing the concert and that the stadium's sod in the VIP section was covered with metal sheeting which had heated up in the sun and burned some attendees who attempted to sit on it.

[27] Swift paused her performance during the Evermore act of the show, noting the fainted audience members, and asked "whoever in charge" to dispense water to them several times during the concert.

[12] Abreu acknowledged that the company could have created shaded areas in the stadium, change the scheduled time for the shows, and emphasized that entry with water cups was allowed.

[3] Swift posted on social media that she was "devastated" by the news: "I can't believe I'm writing these words but it is with a shattered heart that I say we lost a fan earlier tonight before my show.

[36] The mayor of Rio de Janeiro, Eduardo Paes, tweeted that the "loss of a young woman's life [...] is unacceptable" and stated that T4F will be demanded to "provide new water distribution points and more ambulances, and that entry be advanced by one hour".

[35] Congresswoman Erika Hilton, a PSOL member of the national Chamber of Deputies, condemned T4F and filed a complaint on the company with the Ministry of Justice and Public Security, stating that T4F should be held accountable for its "criminal" offense, and introduced a bill draft that would make free water and drinking fountains at concerts mandatory and penalize companies that deny entry to concertgoers carrying water.

[37] Benevides' father, José Weiny Machado, demanded punishment for those responsible for her death and called the water bottle ban "absurd".

[17] On 18 November, the original day of the second Rio de Janeiro show, T4F placed water stations within the venue grounds to cater to the concertgoers.

[43][44] During her second show in Rio de Janeiro, Swift performed "Bigger Than the Whole Sky", a ballad about grief and heartache, which many fans and media interpreted as a tribute to Benevides.

It enshrined many new rules regarding event management, such as allowing attendees to enter with personal bottled water and easy access to free "hydration stations" inside venues.

Niterói, a city in the Greater Rio de Janeiro area, became the first municipality to pass an ordinance guaranteeing water at large events.

[53] An autopsy report of Benevides' body was published on 20 November, which found haemorrhages in her lungs; more tests were ordered to conclusively prove her cause of death.

[55] On 22 November, the Civil Police department of Rio de Janeiro stated an inquiry on T4F was initiated by its consumer delegations wing for "the crime of endangering the life and health" of concertgoers.

Commenting on T4F's claim that the water-bottle ban is a federally mandated rule, The Washington Post confirmed that the Ministry of Justice and Public Security "prohibits venue entry with items that can be thrown and injure a concertgoer, such as capped water bottles".

Milad Haghani, a crowd safety expert at the University of New South Wales, said the lack of assigned seating incentivized conditions which led to overcrowding in the pitch, intensifying the effects of the extreme heat, which may have resulted in more casualties had Swift not taken "quick actions" calling for organizers to distribute water.

[12] In The Washington Post, Kristie Ebi, a professor at the University of Washington's Center for Health and the Global Environment, stated that heat-related illnesses and deaths are preventable but a "coordination among community leaders, event organizers and emergency personnel" is needed to supervise attendees and their protection, highlighting how cities such as Miami, Phoenix and Los Angeles have hired "heat officers"—personnel who are dedicated to preparing for extreme heat events.