* Budapest lab stopped production until filters fixed
* Says iodine-131 emissions remained below health threshold
* Hungary emission not the source of traces in Europe -director (Adds detail, more comments)
BUDAPEST, Nov 17 (Reuters) - Hungarian isotope maker Izotop Intezet earlier this year registered an increase in radioactive iodine-131 emission at its Budapest laboratory and has suspended production until its filters are fixed, it said in a statement on Thursday.
The institute said it first registered an increase in the emissions in the first half of the year and that the level was below the threshold that poses a risk to health. It suspended output between June and August and made adjustments to its filtering system.
In September the institute resumed iodine-131 production, but emissions did not decline to previous levels, so it has stopped output until the necessary further adjustments to its filtering system are made, it said.
Iodine-131, linked to cancer if found in high doses, can contaminate products such as milk and vegetables.
The International Atomic Energy Agency (IAEA) first announced last Friday that traces of iodine-131 had been detected in Europe, after it was tipped off by authorities in the Czech Republic.
The IAEA has said the traces should not pose a public health risk and that it does not think the particles are from Japan's stricken Fukushima nuclear power plant after its emergency in March.
Hungary's Izotop Intezet said it had emitted 300 gigabecquerels (GBq) between January and May and another 324 GBq between September and November -- or roughly 39 percent of its maximum total annual output combined.
"A portion of iodine-131 measured in the atmosphere of Budapest was very likely to have originated from the emission of Izotop Intezet," it said.
"We stress that the emissions have remained below annual limits ... the public exposure is negligible, so the (emissions) have no health or radiobiological consequences."
Mihaly Lakatos, director of the institute, told Reuters that despite the higher than usual emission of the isotope, Hungary could not have been the source of the leakage registered in several European countries over the past weeks.
"The amounts of iodine-131 measured in neighbouring countries cannot have much to do with this, because the distances involved rule out that the amount we emit could be registered over there," he said.
"That is why we have issued this statement to reveal the extent of emission (in Hungary), which if someone looks at (it), they will see that it cannot be the same as what was found covering Europe," Lakatos said.
He said the institute had not been approached by the IAEA for information.
Iodine-131 is a short-lived radioisotope that has a radioactive decay half-life of about eight days.
Experts have said the origin of the radiation, which has been spreading for nearly three weeks, could come from many possible sources ranging from medical laboratories or hospitals, to nuclear submarines. (Reporting by Gergely Szakacs/Krisztina Than; editing by Jane Baird)