highlands acid pit


The Highlands Acid Pit site is assumed to have been used for the disposal of an unknown quantity of industrial waste sludge, from oil and gas refining processes. The site is located near Highlands in Harris County, Texas, at the end of Clear Lake Road, north of Interstate Highway 10. The site is fenced on the north and northeast side, with cluster fencing around all of the monitoring wells. The site consists of a 3.3 acre peninsula within the San Jacinto River 10-year flood plain. The site is bordered by two adjacent active oil/gas production wells and a petroleum distribution center north of the site, flooded sand pits to the east, Clear Lake to the south, and Grennel Slough to the west. A majority of the site is currently clear of brush and trees, with the exception of vegetative overgrowth along the perimeter fencing and on some of the cluster fencing. No structures, except for the monitoring wells and the fencing are currently on the site. Early in the 1950’s, the site received an unknown quantity of industrial waste sludge, believed to be spent sulfuric acid, from oil and gas refining processes. In September 1978, sludge, sediment and storm water sampling was conducted. In October 1981, ground water sampling was conducted. Based on the resulting information, the site was proposed for the NPL with a Hazard Ranking Score of 37.77; it was placed on the NPL in September 1983 Location: 15 miles east of Houston, north of I-10, 1-1/2 miles west of Highlands, Harris County, Texas. Population: Approximately 5,000 people. Setting: The nearest residence and drinking water well is 2,000 feet from the site. The 3.3 acre site is located on a peninsula in the San Jacinto River, surrounded on three sides by water. The site has cluster fencing around all monitoring wells and is currently fenced with locked gate at front north entrance with a grass cover on replacement sand material. Hydrogeology: The site is prone to flooding, and is within 10-year river flood-plain basin. Soils are sandy, approximately 25 ft. deep, with 30 ft. of clay below that. A shallow aquifer in the upper sand is contaminated, and connected to surface water; the next lower aquifer is not contaminated.

Hazardous Ranking Score

38 / 100

A score of 28.5 or higher qualifies a site for the Superfund National Priority List.

Regional Contact

Region 6
Phone: (800) 887-6063

Contact Region



Site Inspection
Preliminary Assessment
Final Listing On NPL

Contaminants & Health Effects

      Endocrine Disrupter
      Reproductive Toxin
      Persistent, bioaccumulative and toxic


        African American
        American Indian and Alaska Native
        Native Hawaiian


        People living
        within a 1 mile radius


        Average Income


        Occupied homes

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