The documents were part of a lawsuit claiming that natural gas extraction through a method known as hydraulic fracturing, or fracking, and storage of the resulting wastewater at a site in southwestern Pennsylvania has contaminated drinking water and sickened seven plaintiffs who live nearby.

In a deposition, a scientist for the Pennsylvania Department of Environmental Protection testified that her laboratory tested for a range of metals but reported results for only some of them because the department’s oiland gas division had not requested results from the full range of tests.

The scientist, Taru Upadhyay, the technical director of the department’s Bureau of Laboratories, said the metals found in the water sample but not reported to either the oil and gas division or to the homeowner who requested the tests, included copper, nickel, zinc and titanium, all of which may damage the health of people exposed to them, according to the federalAgency for Toxic Substances and Disease Registry.

Ms. Upadhyay said that the bureau did not arbitrarily decide to withhold those results. “It was not requested by our client for that particular test, so we did — it is not on our final report,” she said in a deposition on Sept. 26.

Another state environmental official, John Carson, a water quality specialist, testified in a separate deposition that he had received no training in what metals are found in the fluid used in fracking. Critics say that fracking contaminates public water supplies.

The defendants include Range Resources, a leading developer of natural gas in Pennsylvania, and 16 other companies serving the gas industry.

Kendra Smith, a lawyer for Loren Kiskadden, whose water was tested by the Environmental Protection Department, contended that the department purposely avoided reporting the full results of its tests of Mr. Kiskadden’s water in June 2011 and January 2012, after using a method established by the federal Environmental Protection Agency known as 200.7. The method tests for 24 metals, only eight of which were reported, Ms. Smith said.

“Testimony of Ms. Taru Upadhyay was quite alarming,” Ms. Smith wrote Thursday in a letter to Michael Krancer, the state environmental secretary. “She revealed what can only be characterized as a deliberate procedure” by the oil and gas division and the Bureau of Laboratories “to withhold critical water testing results.”

Kevin Sunday, a spokesman for the department, said Ms. Smith had failed to substantiate her “outrageous contention” that the department omitted key markers in tests for substances that typically occur in water samples from drilling in the Marcellus Shale, a rock formation rich in natural gas.

“The battery of analyses we order during investigations are thorough and give us the results we need to make sound determinations, which we fully stand behind,” he said in a statement.

Mr. Sunday said oil and gas division officials wanted to see only the results they deemed relevant to determining whether drinking water was being contaminated by Marcellus Shale gas drilling and production. The remaining metals were present in concentrations that were below federal standards for safe drinking water or had no such standards attached to them, and so were seen as not being useful to the analysis of whether gas drilling was affecting ground water, he said.

Ms. Smith noted that the metals not reported in Mr. Kiskadden’s tests have been identified by industry studies as being found as contaminants in water produced from oil and gas operations.

In the suit, filed in the Washington County Court of Common Pleas in May, Mr. Kiskadden lists health complaints — including nausea, bone pain, breathing difficulties and severe headaches — that he says are consistent with exposure to “hazardous chemicals and gases through air and water.”

Toxicology tests on Mr. Kiskadden and the other six plaintiffs who live within a mile of a Range Resources drill site and wastewater pond in Amwell Township have found the presence of toluene, benzene and arsenic in their bodies, according to the complaint.

The Amwell site is among those the E.P.A. is using in its national investigation into whether fracking affects groundwater and drinking water.

Companies like Range Resources insist that chemicals used in fracking cannot enter public water sources because they are insulated from aquifers by multilayered steel and concrete casings and are deployed a mile or more underground beneath thousands of feet of impervious rock.

State Representative Jesse J. White, a Democrat who represents part of Washington County, accused the Environmental Protection Department of manipulating water tests to hide what he called “adverse results” from gas-drilling operations.

Range Resources did not return calls seeking comment, but the Marcellus Shale Coalition, an industry group, said that the state lab had been endorsed as “well-managed, efficient and highly functional” by the Association of Public Health Laboratories.

By JON HURDLE. John Schwartz contributed reporting from New York.