Methane gas detector

There was this abandoned lot found here in our village which is already for sale. The people here remembered that area was a old factory before. They say that it would not be safe to build a house in there. After the officials in here made a thorough surveylance, test and check up of the lot it was found out it was a save area for residential. They also said that they used also a methane gas detector. As of now there are many investors as well as realtors who are interested to build that area in commercial or residential center.