Miami-Dade County’s inspector general is asking questions about the integrity of structural elements of the sliding roof on the new Miami Marlins stadium in Little Havana, after learning that a subcontractor allegedly falsified inspection reports on some critical welds.

The Marlins and their engineers embarked on a flurry of re-inspections after being alerted to the apparently falsified inspections more than a year ago, internal letters and documents collected by the IG’s office and obtained by The Miami Herald show. Some of the re-inspections led to repairs of welds that were substandard, the documents show.

In their most recent letter to the IG, dated Nov. 29, the team and its engineers say they are satisfied there are no safety or structural issues with the steel roof supports, but are conducting further tests of the welds in question “in an abundance of caution.’’

Marlins president David Samson said Tuesday the team welcomed the IG’s review.

“We want inspections," Samson said. “That’s great for us. I hope he’s looking at everything in the ballpark — everything.’’

Inspector General Christopher Mazzella, whose office has inspectors on site at the stadium everyday, declined to comment Tuesday.

Mazzella’s review appears aimed at ensuring that the re-inspections and repairs were adequate and that city of Miami building officials were fully apprised of and approved the work. The welds join pieces of the giant curving trusses holding up the stadium’s retractable roof, the steel rails on which the roof slides, as well as the wheeled “transporters’’ that join the roof structure to the rails.

In a Nov. 2 letter to the Marlins, Mazzella asked a series of technical questions about the re-inspections and standards used to conclude that welds were acceptable. The documents indicate that the Marlins’ engineers changed specifications for some welds after re-inspecting them, and Mazzella asked that any revised designs be provided to the city for review.

Reached late Tuesday, Assistant City Manager Alice Bravo, who oversees the building department, said she understood all the issues raised in that letter have been “resolved.’’

City Commissioner Marc Sarnoff, a critic of the publicly financed stadium deal, said he was satisfied after reviewing the documents collected by the inspector general.

“The engineer of record has indicated it’s a structurally sound building,’’ Sarnoff said.

The issue of the flawed inspections and welds came to light on Tuesday, a day when the Marlins conducted a media tour of the nearly complete $634 million stadium.

Miami Herald news partner WFOR-CBS 4 reported that a welder and inspector on the stadium project, Roy Fastabend, alleged that the Marlins and its contractors cut corners on inspections and fabrication of the roof structural elements.

Fastabend told WFOR that he was fired after blowing the whistle on another inspector, Mike Garcia, who allegedly signed off on some welds without actually inspecting or testing them. Fastabend also said he pointed out problems earlier in the construction process, including that a subcontractor allegedly was using weaker welds than the plans called for.

“If people knew what was going on there, or how they did things — I mean, I won’t go to that stadium,’’ Fastabend told the television station. “I won’t take my kids into that place.’’

The documents show that the Marlins’ general contractor, Hunt/Moss, alerted the ball club to the flawed inspections by Garcia, who worked for a subcontractor, in September of 2010, though the questionable inspections were conducted the previous spring. Garcia was replaced on the job on May 24 and apparently later fired.

Hunt/Moss had all welds that had been inspected by Garcia re-inspected with a variety of methods, including visual inspection and ultrasonic testing, the documents indicate. Some welds were repaired. In some cases, engineers concluded that other welds, while not done to standards called for in the plans, were nonetheless more-than strong enough to withstand roof stresses.

The private engineer of record on the job, Bliss & Nyitray, on whom the city relies to certify work at the stadium, signed off on the new inspections, repairs and recalculations, the city of Miami’s chief building official, Mariano Fernandez, said Tuesday.

The firm “reviewed the allegations and has accepted the corrections or recalculated the weldings and we have accepted that. As long as the threshold engineer is happy, we’re happy,’’ Fernandez said.

He said Garcia was supposed to inspect the welding jobs at several plants around the United States where the structural materials were fabricated.

He said the city will do a final inspection before the park opens in April.