New questions raised about what was mixed with nuke waste that leaked

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New questions are being raised about what was mixed with the waste that caused a radiation release at the government's nuclear waste dump in southeastern New Mexico.

The Albuquerque Journal reports Thursday ( ) that Los Alamos National Laboratory approved using products that some experts say are widely known to cause a heat reaction when mixed with other contents in the drums that were shipped to the Waste Isolation Pilot Plant near Carlsbad.

While officials have said one key theory is the leak may have been caused by a reaction from a switch in the type of cat litter packed with the waste to absorb moisture, emails made public by the state show Los Alamos approved using other organic ingredients known to be incompatible with nitrate salts in the waste.