A grand jury has charged the biggest material testing laboratory in the New York City area and key employees, seven of them professional engineers, with systematically falsifying results and overbilling clients. The alleged crimes took place over the last five years and involved some of the areas biggest projects, including the new Yankee Stadium and the Freedom Tower at Ground Zero in Manhattan.

The grand jury and Manhattan District Attorney Robert Morgenthau charged that Testwell Group failed to perform tests, falsified reports and double-billed clients for field work. The company also lacked certification for inspectors it said were certified, according to the charges.

With the indictment, prosecutors obtained a court order freezing the firm’s assets and the assets of the defendants. It isn’t clear if this essentially ends Testwell’s operations or if the company is still at work. Reached by phone, the company’s office manager declined to answer questions and the company’s sole owner and chief executive, V. Reddy Kancharla, could not be reached for comment. An attorney for Testwell, Martin Adelman, says that Testwell is “disappointed with the charges and will contest them vigorously and looks forward to the restoration of its image in the construction industry.”

The indictments come amid a larger effort to enforce safety at New York-area construction sites following two fatal crane accidents in Manhattan. In the crane probes, prosecutors charged a New York City buildings department inspector with falsifying tower crane inspection reports.

To what extent structures completed or under construction will have to be retested because of the Testwell allegations was not immediately clear.

Testwell Laboratories Inc., a key unit of Testwell Group, achieved a rank of 36 on New York Construction’s Top Specialty Contractors, with reported revenue of $21.5 million earned in the tri-state area in 2007.

The grand jury and Manhattan District Attorney Robert Morgenthau charged Testwell with enterprise corruption, the equivalent of a racketeering charge, because of the systematic nature of the alleged crimes. Essentially, the charges involve separate schemes involving mix design, field tests, compressive strength, steel inspection and certification. According to the charges, Testwell performed only six to eight “legitimate” mix design tests each year but instead completed “roughly 200-300 phony” design mix reports.

The investigation began when the Port Authority of New York and New Jersey and the New York Yankees forwarded information about improper testing on the Freedom Tower and at the new Yankee Stadium in the Bronx. The district attorney conducted searches of Testwell’s Ossining, N.Y. headquarters in June, August and just prior to the indictment.

At the new Yankee Stadium, according to the charges, Testwell employees entered density test results from the field on final reports even though the handwritten field test reports had not been entered. Air content report results were entered even though the field reports contained no information. The same pattern existed on other New York City projects, according to the charges.

A potentially more sensitive series of false reports involves the concrete for the Freedom Tower. From May 2006 until Sept. 2006, Testwell certified that the concrete reached or exceeded 12,000 psi of compressive strength. When the Port Authority tested the concrete, however, the concrete averaged around 10,000 psi. Later core tests showed some of the concrete had cured to only 9,000 psi, according to the prosecutors.

According to the prosecutors, officials of the Dormitory Authority of New York State turned up numerous discrepancies on steel inspection reports made by Testwell on a large college expansion project. Some steel sections were shown to have been inspected over and over while more than half of the project’s “welded pieces that Testwell certified as accurately inspected were in storage at the facility and had never been tested.”

Prosecutors listed Kancharla, Testwell’s owner, and six other employees as professional engineers. One of them is Vincent Barone, vice president in charge of engineering. Prosecutors claim that another engineer, Edward Porter, was in charge of preparing concrete mix design reports and that engineer Michael Sterlacci was “primarily employed...to sign and stamp documents for Testwell that required a professional engineer’s seal.”