Perpetrated by anti-government extremists Timothy McVeigh, the mastermind,[3][4][5] and Terry Nichols, the bombing occurred at 9:02 a.m. and killed 167 people, injured 684, and destroyed more than one-third of the building, which had to be demolished.

In response to the bombing, the U.S. Congress passed the Antiterrorism and Effective Death Penalty Act of 1996, which limited access to habeas corpus in the United States, among other provisions.

[30] He later decided to bomb a federal building as a response to the raids and to protest what he believed to be U.S. government efforts to restrict rights of private citizens, particularly those under the Second Amendment.

Potential targets in this campaign included United States Attorney General, Janet Reno, and FBI Hostage Rescue Team sniper, Lon Horiuchi.

[38] He said in his authorized biography that he wanted to minimize non-governmental casualties, so he ruled out Simmons Tower, a 40-story building in Little Rock, Arkansas, because a florist's shop occupied space on the ground floor.

[42] Though his execution was not confirmed to be a motive for the bombing, Fort Smith–based federal prosecutor Steven Snyder told the FBI in May 1995 that Snell wanted to blow up the Oklahoma City building as revenge for the IRS raiding his home.

McVeigh rented a storage space in which he stockpiled seven crates of 18-inch-long (46 cm) Tovex "sausages", 80 spools of shock tube, and 500 electric blasting caps, which he and Nichols had stolen from a Martin Marietta Aggregates quarry in Marion, Kansas.

[58][59] On April 16, 1995, he and Nichols drove to Oklahoma City, where he parked a getaway car, a yellow 1977 Mercury Marquis, several blocks from the Murrah Federal Building.

[63] They then drove to Geary Lake State Park, where they nailed boards onto the floor of the truck to hold the 13 barrels in place and mixed the chemicals using plastic buckets and a bathroom scale.

These time-delayed fuses led from the cab through plastic fish-tank tubing conduit to two sets of non-electric blasting caps which would ignite around 350 pounds (160 kg) of the high-grade explosives that McVeigh stole from a rock quarry.

[41] He also carried an envelope full of revolutionary materials that included a bumper sticker with the slogan, falsely attributed[71] to Thomas Jefferson, "When the government fears the people, there is liberty.

[75] At 9:02 a.m. (14:02 UTC), the Ryder truck, containing over 4,800 pounds (2,200 kg)[76] of ammonium nitrate fertilizer, nitromethane, and diesel fuel mixture, detonated in front of the north side of the nine-story Alfred P. Murrah Federal Building.

[13] Investigators discovered incriminating evidence at his home: ammonium nitrate and blasting caps, the electric drill used to drill out the locks at the quarry, books on bomb-making, a copy of Hunter (a 1989 novel by William Luther Pierce, the founder and chairman of the National Alliance, a white nationalist group) and a hand-drawn map of downtown Oklahoma City, on which the Murrah Building and the spot where McVeigh's getaway car was hidden were marked.

[118][127] The device was determined to be a three-foot (.9-m) long TOW missile used in the training of federal agents and bomb-sniffing dogs;[6][128] although inert, it had been marked "live" in order to mislead arms traffickers in a planned law enforcement sting.

The United States will not tolerate it, and I will not allow the people of this country to be intimidated by evil cowards.He ordered that flags for all federal buildings be flown at half-staff for 30 days in remembrance of the victims.

President Clinton received many messages of sympathy, including those from Queen Elizabeth II of the United Kingdom, Yasser Arafat of the Palestine Liberation Organization, and P. V. Narasimha Rao of India.

A photograph of firefighter Chris Fields emerging from the rubble with infant Baylee Almon, who later died in a nearby hospital, was reprinted worldwide and became a symbol of the attack.

The photo, taken by bank employee Charles H. Porter IV, won the 1996 Pulitzer Prize for Spot News Photography and appeared on newspapers and magazines for months following the attack.

[164] On April 22, 1995, the Clintons spoke in the White House with over 40 federal agency employees and their children, and in a live nationwide television and radio broadcast, addressed their concerns.

[171] As the rescue effort wound down, the media interest shifted to the investigation, arrests, and trials of Timothy McVeigh and Terry Nichols, and on the search for an additional suspect named "John Doe Number Two."

[178] OKBOMB was the largest criminal case in America's history, with FBI agents conducting 28,000 interviews, amassing 3.5 short tons (3.2 t) of evidence, and collecting nearly one billion pieces of information.

The defense was allowed to enter into evidence six pages of a 517-page Justice Department report criticizing the FBI crime laboratory and David Williams, one of the agency's explosives experts, for reaching unscientific and biased conclusions.

"[213] In the years since the bombing, scientists, security experts, and the ATF have called on Congress to develop legislation that would require customers to produce identification when purchasing ammonium nitrate fertilizer, and for sellers to maintain records of its sale.

[218] On April 6, 2010, House Bill 2750 was signed by Governor Brad Henry, requiring the bombing to be entered into the school curriculum for Oklahoma, U.S. and world history classes.

[232] Among the 52 security improvements were physical barriers, closed-circuit television monitoring, site planning and access, hardening of building exteriors to increase blast resistance, glazing systems to reduce flying glass shards and fatalities, and structural engineering design to prevent progressive collapse.

The National Geographic Channel documentary series Seconds From Disaster suggested that the Murrah Federal Building would probably have survived the blast had it been built according to California's earthquake design codes.

In evidence he cited the peaceful resolution of the Montana Freemen standoff in 1996, the government's $3.1 million settlement with Randy Weaver and his surviving children four months after the bombing, and April 2000 statements by Bill Clinton regretting his decision to storm the Branch Davidian compound.

After the September 11 attacks in 2001, with consideration of other events, including the Oklahoma City bombing, the Federal Highway Administration proposed that major metropolitan areas create evacuation routes for civilians.

[242] For two years after the bombing the only memorials to the victims were plush toys, crucifixes, letters, and other personal items left by thousands of people at a security fence surrounding the site of the building.

[260] President George W. Bush made note of the anniversary in a written statement, part of which echoed his remarks on the execution of Timothy McVeigh in 2001: "For the survivors of the crime and for the families of the dead the pain goes on.