Whether the canned food is the factor that contributes to the lead poisoning and the death

1. Company has limited time to finish this work. Workers are under time pressure and it is reasonable that they are careless and apply lead to the cans in a hurry way.
2. First, it is difficult to judge whether sailors are affected by lead without careful tests. Second, the symptoms of lead poisoning are common, such as feeling tired or headache and they can be easily overlooked.
3. The water in the purification system is used for ship engineering since the salt water cannot be used

1. The lead that was carefully stilled to the can would not contact the food.
2. No other evidence of death of the crew was found in other ship.
3. Water purification system may be the source of poisoning.