Questions have been raised about environmental dangers to La Brea residents if a US$1 billion aluminium smelter is sited there. [United National Congress] senator Carolyn Seepersad-Bachan...said there had been calls from several quarters over environmental concerns surrounding the building of a smelter at the site. She said a smelter produced hydrogen fluoride gas which was toxic if it exceeded three parts per million in the atmosphere... [refers to Alcoa, Sural]