The US spent nearly $300 million on anti-radiation pills.
The US Department for Health and Human Services purchased a supply of the drug Nplate from the company.
Acute radiation syndrome can occur when a person's entire body is exposed to a high dose of penetrating radiation in a matter of seconds.
The drug stimulates the body's production of platelets, fighting symptoms of ARS which include uncontrollable and life threatening bleeding due to a loss of those platelets
The purchase was part of an ongoing effort to prepare for a wide range of threats including chemical, biological, radiological, nuclear and emerging infectious diseases, according to an HHS spokesman.
Russian President Putin made a threat to use nuclear weapons as he announced a partial deployment of troops.
The US accuses Putin of "saber-rattling" and says there is no evidence that Russia is planning to use nuclear weapons. The director of the CIA said it was difficult to say if Putin was bluffing about using the weapons.
Zelenskyy said that Russia was preparing for a nuclear war but that Putin wasn't ready to do it.
There are concerns that Putin could use smaller tactical nuclear weapons in response to the slowing of Russia's progress in its invasion of Ukraine.
US President Joe Biden said he didn't think Putin was joking when he said he would use nuclear weapons.
The president said that they have not faced the threat of armageddon since the Cuban missile crisis.