If the operator did not assemble enough characters, the line will not justify correctly: even with the spacebands expanded all the way, the matrices are not tight. A safety mechanism in the justification vise detects this and blocks the casting operation. Without such a mechanism, the result would be a "squirt" of molten type metal spraying out through the gaps between the matrices, creating a time-consuming mess and a possible hazard to the operator. If a squirt did occur, it was generally up to the operator to grab the "hell bucket" and catch the flowing lead. It was so called because the bucket would often "go to hell", or melt, while holding the molten lead that was still extremely hot. Also, in conjunction with possible hazards facing an operator, toxic lead fumes were possible, as they were the result of melting the lead ingots for casting.