I lurk in unseen places and do most of my work silently.

You are warned against me, but you do not always heed.

I am relentless.

I am everywhere—in the house, on the streets, in the factory, at the railroad crossings, and on the sea.

I bring sickness, degradation and death, yet few people seek to avoid me.

I destroy, crush, or maim; I give nothing, but take all.

I am your worst enemy.

I spare no one, and I find my victims among the rich and poor alike, the young and old, the strong and weak. Widows and orphans know me.

I cast my shadow over every field of activity, from the turning of the grindstone to the moving of a railroad train, from the rocking of a boat to the spinning of a top.

Do you know who I am?