Sue Pearsall/Enr Bloomberg (center) called failure 'unacceptable.'

People who work around cranes and the innocent bystanders who regularly walk underneath them are understandably nervous. Two fatal crane collapses in New York City in less than three months and a slew of other lapses around the country have called into question the regulations and procedures for operating, rigging, inspecting, maintaining and repairing cranes, including self-climbing tower units. And construction experts are investigating and wondering whether the existing slate of local, state and national rules are enough to keep workers out of harm’s way.

It so far has been a bad year for crane accidents, which have on average claimed nearly 82 lives each year since 1997, according to to U.S. Dept. of Labor. But fatalities in the first six months are more than double last year’s pace with the deaths of 43 workers, according to the Internet-based safety clearing-house www.craneaccidents.com.

AP/Wideworld

AP/Wideworld Vintage Kodiak crane snapped on May 30, raising maintenance concerns.

Globally, the rate of crane fatalities are up 44%. The disasters have flowed in a steady stream, with a March 15 fatal collapse in midtown Manhattan followed by more crane accidents in Florida, Maryland, Illinois, Texas, Wisconsin, California, Iowa, Pennsylvania, Indiana, Missouri, again on New York City’s Upper East Side on May 30 and others on the Las Vegas Strip and in Wyoming. The incidents have sparked domestic crane sweeps and policy and regulatory reviews.

The public, already wary after New York’s Midtown accident in March, on May 30 saw a Kodiak-brand crane’s turntable, cab and luffing boom snap from its steel-trussed tower while working at a high-rise apartment building on Manhattan’s Upper East Side. The debris and equipment rained down on a nearby apartment building, killing operator Donald Leo, 30, and worker Ramadan Kurtaj, 27, trade unknown. No load was on the hook. Leo was a member of operating engineers’ union Local 14.

City officials evacuated eight nearby buildings, totaling about 160 apartments. Tony Vasquez, a nearby resident, said the falling crane “sounded like a big explosion.”

City inspectors had stopped work at the site twice in late April, once because the crane failed a load test and soon after because the operator lowered the boom incorrectly and damaged a limit switch. The switch was fixed and work resumed.

Unlike the March accident, this one left the tower still fastened to the building. The collapse occurred at 8 a.m. while crews were working on floors 10, 11 and 12 at the Azure, a 241,000-sq-ft, 32-story condominium and school led by local contractor DeMatteis Organizations.

Tudor Van Hampton/Enr Crane King. Lomma says he would like to see crane-inspection requirements improve.

Robert LiMandri, acting commissioner of the New York City Dept. of Buildings, says the crane is owned by New York Crane & Equipment Corp. Another firm, Sorbara Construction, based in Lynbrook, N.Y., was operating the crane as a sub performing concrete work.

“What has happened was unacceptable and intolerable,” said Mayor Michael Bloomberg. “We do not at the moment know exactly what happened or why. It would appear the constructor and the building department followed regulations. Whether those are appropriate or not we will have to see.”

After the March 15 accident, the city required inspectors on every tower-crane jump but backed off the policy on May 28 after a review of 49 jumps found only two with problems. The Kodiak was not jumping when it fell but jumped days before the accident and received a clean bill of health by city inspectors on May 29.

By afternoon on the day of the accident, investigators from the U.S. Occupational Safety and Health Administration, city and industry already were eyeing...