Its radiation can make normal cells cancerous. For that reason, it was headline news a number of years ago when two scientists from the University of California announced they had found a substance that could remove plutonium from living tissue. Today, man is rightly concerned about the importance of decontamination. But long ago, God showed mankind the more critical need for spiritual cleansing.
Bronze symbolizes judgment.
God was teaching His people that after He had provided a sacrifice at the altar, a continual self-judging and cleansing from personal defilement was necessary. This principle still applies today. The road to worship begins at the cross.