These were among the 51 samples collected in December. The results of the samples picked up in January are yet to come.

Delhi Health Minister A K Walia says recycling is a possibility. ``There is a possibility that the adulterated oil had been recycled,'' he says. ``We have checked other batches of the oil from the same mills, but we have not found them to be adulterated,'' he adds. ``We have a feeling that some of the oil in one batch may have been changed.''

However, the Health Minister is not sure at what stage the adulteration takes place. ``I cannot say whether it is the traders or the manufactures. But we are giving them a chance to come clean and check the adulteration,'' he says.

``Because if we askthem what has happened to the adulterated oil that was sealed last year, they just say that they have disposed it of,'' says the minister.

Botanists feel that it is part of the same crop which was used for mustard oil last year which had caused dropsy. Being an annual crop, mustard seeds are available only once a year in February-March.

Says Dr A.K. Bhatnagar, professor of Botany in Delhi University: ``The last crop might have come mixed with argemone, as it also has similar looking seeds. It is not necessary that the two were mixed on intent.''

He also feels that oil that was sealed in September last year could still test positive for adulteration because the contamination does not decrease with time.

Earlier, the spokesperson of Puri Oil Mills, whose sample has failed the test, said: ``The same batches of oil passed the test in Chandigarh PFA department, how can they fail here?'' Following their representation, a recheck of the samples was carried out but the samples still failed.

The traders,however, do not agree with the Government's stand. Naresh Aggarwal, of Hanuman Agro Industries, says, ``How can they say recycled? It could be due mix of mustard seed with argemone, something that the manufacturers cannot prevent or detect.''

Karan Joshi, an oil dealer in Naya Bazar says, ``The oil that was sealed in September last year would have got spoilt by now. It cannot be recycled.''

Mustard oil, a very common ingredient of cooking, was off the shelves a few months ago because of the deadly argemone adulteration. The adulteration causes dropsy, a disease which took proportions of an epidemic in September last year.

Following a series of raids, godowns with hundreds of litres of adulterated mustard oil were sealed.