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Open Access Publications from the University of California

Day-glo fluorescent particles as a marker for use in M-44 cyanide capsules

  • Author(s): Burns, Richard J.
  • Connolly, Guy E.
  • Savarie, Peter J.
  • et al.

Tracerite®, the chemical marker used in M-44 cyanide capsules, contains cadmium which the Environmental Protection Agency identified as an inert ingredient of toxicological concern. An alternative nontoxic marker was identified and tested. In a weathering test, capsules with Day-Glo® performed as well as those containing Tracerite, and presence of potassium chloride in the capsules did not improve capsule function. Day-Glo was further tested by allowing captive coyotes to discharge M-44s containing sodium cyanide and various colors of Day-Glo. Twelve of 13 coyotes that died or were euthanized soon after recovering from sublethal doses had obvious marks in their mouths for 4 to 5 weeks. On the basis of these tests, the registered formulation for M-44 capsules was changed; Tracerite and KCl were deleted and Day-Glo Blaze Orange was added.

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