Animation producers remained stumped Wednesday as to why techniques that have been used "hundreds of times" sent "Pocket Monster" viewers to the hospital Tuesday night.

"We are taking the situation very seriously," said Takemoto Mori, the program producer at Shogakukan Production Co. "But we cannot understand why it turned out this way, since we did not use any special technique."

Mori said Tuesday's episode included a technique called "paka-paka," in which different colored lights flash alternately to cause a sense of tension, and another called "flash" in which a strong beam of light is emitted. These techniques are commonly used in animation, Mori said, stressing that they do not constitute foul play.

A producer at another TV station agreed. "The paka-paka technique is classic and has been used hundreds of times in the past," he said. "But I have never heard of such damage stemming from the technique."

He suspects that the incident occurred because a climactic scene intensified the two techniques. "If this technique were to be banned, the animation production would be destined to change," the producer added.

Most animation shows are contracted out, and each station checks the programs prior to their airing. The producers and the station screened Tuesday's episode of "Pocket Monsters" separately, resulting in a double-screening, according to its producers.

The incident caused other stations to be cautious with their animation shows. TV Asahi expressed fear that it would result in "villainization" of TV animation.