Embarq's building at 503 Ash St. is one of eight extremely hazardous substance sites within Boulder City's jurisdiction -- the only one in the urban core of the city. It was identified in the Clark County Hazardous Materials Response Plan approved by the County Commission on Feb. 20. The Embarq site is one of six sites containing sulfuric acid, with 1,054 pounds of the chemical. The other sulfuric acid sites are Hoover Dam (32,250 pounds), the Colorado River Commission east substation (5,330 pounds), Eldorado Energy (5,000 pounds), the Mead substation (3,227 pounds) and Willtel Communications in Eldorado Valley (1,296 pounds). Sulfuric acid is an oily, colorless corrosive liquid. The Southern Nevada Water System at Lake Mead is the county's leading site of anhydrous ammonia (606,800 pounds) and is a distant second to Pioneer Americas LLC at the BMI Complex in Henderson, which has nearly eight times as much chlorine (204,000 pounds).