A human right group, Concerned Nigerians has threatened to embark on a mass protest across the country against the Nigerian National Petroleum Corporation (NNPC) for shielding companies and individuals responsible for the importation of contaminated fuel into the country.The group said the NNPC lacked the political will to punish the offenders, adding that the corporation had been compromised to permit all manners of contaminated products into the country to the detriment of law-abiding Nigerians.