The rising prices for scrap metal has made manhole covers attractive to thieves. They are generally accessible and unsecured and often in locations where a truck can be pulled up right to them. Even so, many weigh in excess of 100 pounds, which makes them difficult to take. Legitimate scrap dealers will not accept them if they don’t know where they came from, though thieves make break them into pieces or hide them in a load of scrap.
There has been much news coverage of this lately, and several stories are linked below.
Manhole covers stolen in Long Beach
New street crime: Thieves lift manhole covers
Poking a hole in manhole cover thieves' plans
Spate Of Manhole Cover Thefts Poses Problem