FLC OF A CARGO B757 DIVERTED TO LAND AFTER SMELLING A STRANGE ODOR COMING FROM A CARGO BIN. AFTER LNDG INSPECTION OF THE BIN REVEALED ICE FOG. IN ADDITION THE HAZMAT FORM DID NOT REFLECT THE ACTUAL WT OF THE DRY ICE CARRIED RESULTING IN EXCEEDING THE MAX DRY ICE WT ALLOWED FOR THE TYPE OF ACFT.

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I WAS CONDUCTING OPERATIONAL EXPERIENCE (WITH A TRANSITION CAPT) AND WAS SITTING IN THE FO'S SEAT. I WAS THE PIC. OUR GND PERSONNEL BROUGHT A 'HAZMAT NOTIFICATION TO THE PIC' SLIP TO THE FLT DECK. I DID NOT SIGN THE SLIP; BUT THE OPERATIONAL EXPERIENCE CAPT DID. WE DEPARTED OUR ORIGIN STATION; AND APPROX 40 MINS LATER; DIVERTED TO DTW AS WE HAD A STRANGE ODOR ON THE FLT DECK THAT SEEMED TO BE PERCEPTIBLE FOR ONLY A MIN OR SO; AND THEN GO AWAY. WE CONTACTED DISPATCH AND MAINT CTL TO ADVISE THEM OF OUR SIT; AND TO INQUIRE ABOUT THE SHIP'S HISTORY. WHILE TALKING TO THEM WE RECEIVED AN EQUIP OVERHEAT INDICATION. WE PERFORMED OUR ABNORMAL PROCS; AND DISPATCH RELEASED US TO DTW. OUR FLT ATTENDANTS WERE BRIEFED FOR THE DIVERSION. AFTER LNDG AND ENGS SHUT DOWN; THE ARPT RESCUE AND FIRE FIGHTING TEAM INSPECTED OUR ACFT; AND CLRED US TO PROCEED TO OUR GATE. ON ARR AT OUR GATE; OUR FORWARD CARGO COMPARTMENT WAS FOUND TO BE 'FROZEN.' OUR HAZMAT SLIP INDICATED WE HAD DRY ICE ON BOARD. WE HAD 21 PIECES EACH WEIGHING 22 LBS. WE THOUGHT THEY MEANT 2.2 LBS AS THAT IS THE LB WT OF A KILOGRAM. THIS WAS INTERPED AS 46.2 LBS WHICH IS SLIGHTLY MORE THAN USUALLY OBSERVED ON OUR FLTS; BUT FAR LESS THAN THE AUTH 440 LBS THAT OUR B757'S ARE AUTH TO CARRY. OUR HAZMAT SLIP SHOULD HAVE INDICATED EITHER KILOGRAMS OR LITERS; BUT WE ASSUMED THE 22 LB WT TO BE A COURTESY CONVERSION OF A KILOGRAM TO LBS BY OUR CARGO PERSONNEL. OUR ASSUMPTION WAS WRONG; AND SHOULD HAVE PROMPTED AN INQUIRY AS TO THE EXACT WT OF THE DRY ICE. IN THE FUTURE I WILL ASSUME NOTHING; AND ALSO ENSURE THAT I; AS THE PIC; SIGN THE HAZMAT SLIP. I ALSO BELIEVE THAT A VISUAL CONFIRMATION OF THE CARGO IS A GOOD IDEA AS A VISUAL ON THE CARGO WOULD HAVE BEEN AN EXCELLENT CLUE THAT WE HAD 462 LBS OF DRY ICE INSTEAD OF 46.2 LBS.