New York City officials told Congress on Tuesday they are tightening requirements on tower construction cranes after a spate of recent accidents there, as well as others in Las Vegas and Miami.

Robert LiMandri, the city's acting Buildings Commissioner, testified before a House Education and Labor Committee hearing examining whether there are insufficient safeguards in place for cranes used at high-rise construction sites.

LiMandri says the city will impose tougher maintenance and inspection requirements at sites with tower cranes, including documenting a history of maintenance and major repairs to critical crane parts.

"I'm deeply troubled" by the string of recent fatalities, LiMandri said, but he added, "It is simply impossible for our inspectors to be at every site at all times."

He said the federal Occupational Safety and Health Administration needs more manpower to help keep construction sites safe, and urged lawmakers to provide extra money for more federal inspectors.

Crane safety is getting extra scrutiny following an alarming number of crane-related deaths in recent months. In New York City, two crane accidents since March have killed nine people -- a greater number than the total deaths from cranes over the past decade.

Nationwide, on average, four construction workers are killed every day in the United States in construction site accidents.

"There's no question that construction is an inherently dangerous job," said committee chairman George Miller, D-Calif. "The question is whether more can be done to prevent accidents and make the industry safer."

Assistant Secretary Edwin Foulke of OSHA said the overall safety record is good and getting better.

"If you look at fatality rates in both general industry and construction, they have been continually going down... I think our efforts are working," Foulke told the committee.

Many states have no count of their cranes, nor do they mandate training for workers who run the equipment, or for officials who certify crane operators. Even the federal government acknowledged last month that updated standards would prevent some crane accidents.

New York City has only four inspectors on the payroll to inspect more than 200 cranes, 26 of them large tower cranes. About four inspections are conducted each day, a routine that industry veterans say won't detect real problems such as the rebuilt crane part blamed for one of the New York crane collapses.

Ironworker George Cole told the panel he blamed OSHA for the death of his brother-in-law Rusty Billingsley from a fall at a construction site in Las Vegas.

Foulke said he was unfamiliar with the exact details of Billingsley's death, but sought to assure the committee the agency has expanded crane inspections in New York, and is working on a nationwide crane safety initiative to reinforce regulations and safe practices.

The agency issued 24,358 citations last year for violations of fall safety rules at construction sites, leading to more than $33 million in fines, said Foulke.