Two years before Saturday's deadly balloon crash near Lockhart, the National Transportation and Safety Board warned of the potential for a "high number of fatalities in a single air tour balloon accident" if federal officials did not adopt stricter regulations of air tour balloon operators.

In the April 2014 letter to the Federal Aviation Administration, the NTSB recommended that hot air balloon operators get similar levels of safety oversight as airplane and helicopter tour operators. The safety board cited several recent U.S. balloon accidents, as well as a 2013 accident in Egypt that killed 19.

“Based on the number of recurring accidents in the United States involving similar safety issues, the NTSB believes that air tour balloon operators should be subject to greater regulatory oversight,” safety officials wrote to the FAA.

Deadly hot air balloon crash in Texas: What we know now

At the time, the Balloon Federation of America, a trade group, called the recommendations "unnecessary and burdensome" and instead called for a partnership with federal agencies to improve tour operator safety.

The FAA rejected the NTSB’s recommendations in November, determining that they would not result in a “significantly higher level of operational safety.”

The FAA further wrote that “Since the amount of ballooning is so low, the FAA believes the risk posed to all pilots and participants is also low” and that “the FAA regularly attends sanctioned ballooning events and performs certain oversight activities, such as checking pilot credentials and reviewing the airworthiness condition of the balloon.”

Photos: Fatal balloon crash in Texas

The NTSB blasted the FAA’s response as unacceptable.

“We are concerned that, if no action is taken to address this safety issue, we will continue to see such accidents in the future,” the agency wrote in March. “Since these recommendations were issued in April 2014, an additional 25 balloon accidents have occurred, resulting in four fatalities and 25 serious injuries.”

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The safety board found that recent accidents revealed “operational deficiencies” in commercial air tour balloon operations such as operating in unfavorable wind conditions and the failure to follow flight manual procedures. The safety board said it was concerned the accidents were the “result of the current lack of oversight relative to similar airplane and helicopter air tour operations.”

The NTSB determined that a 2013 balloon crash in Pennsylvania, which resulted in several serious injuries, was a result of “the pilot’s failure to extinguish the burner pilot lights prior to a hard landing in windy conditions.”

A 2013 study found that between 2000 and 2011, balloon crashes resulted in 91 serious injuries and five deaths. The study found the deaths all came after balloons hit fixed objects like power lines and trees. The study also found that the proportion of balloon crashes attributed to paid rides appears to have increased over time.

Other reports have found that since 1964, there have been 114 fatalities from balloon crashes.

NTSB records show four balloon crashes prior to Saturday's accident in 2016, including one incident in which a ground member was killed while trying to secure a basket during an unintentional liftoff in New York.

The most recent Texas crash occurred in July 2015 in Longview when a pilot aborted a landing during high winds to avoid power lines and landed in an adjacent field, breaking his hip and ankle.