HIGHLANDS ACID PIT
On this page:
- What Is Being Done to Clean Up the Site?
- What Is the Current Site Status?
- EPA’s Involvement at the Site
- Activity and Use Limitations
- Emergency Response and Removal
- Operable Units (opens new page)
- Cleanup Progress (opens new page)
The 3.3-acre Highland Acid Pit site is located in Highlands in Harris County, Texas, on a peninsula in the San Jacinto River 10-year floodplain. Early in the 1950s, the area received an unknown quantity of industrial waste sludge, believed to be spent sulfuric acid, from oil and gas refining processes. The waste disposal activities contaminated soil and groundwater with hazardous chemicals. Following cleanup, operation and maintenance activities and monitoring are ongoing.
What Is Being Done to Clean Up the Site?
The site is being addressed through federal and state actions.
Remedy construction and operation have effectively reduced risk from 22,000 cubic yards (33,000 tons) of contaminated industrial sludge. The San Jacinto River has been protected from off-site migration of wastes, precluding fish kills similar to prior events.
EPA has conducted five-year reviews at the site. These reviews ensure that the remedies put in place protect public health and the environment, and function as intended by site decision documents. The most recent review concluded that response actions at the site are in accordance with the remedy selected by EPA and that the remedy continues to be protective of human health and the environment in the short term. Long-term protectiveness requires semi-annual groundwater monitoring, evaluation whether additional action is necessary for chemical concentrations above cleanup levels, implementation of surface water and sediment monitoring, and upkeep of wells and other site maintenance.
What Is the Current Site Status?
The site’s long-term remedy for source control, selected in 1984, included excavation of waste and contaminated soil with off-site disposal. The remedy also included backfilling the excavation, revegetation and installation of a fence. Cleanup removed 22,200 cubic yards of waste and soil from the site. Cleanup finished in December 1987. Institutional controls, including a deed notice, were implemented.
The long-term remedy for groundwater, selected in 1987, was “no action.” Despite its name, the "no action" remedy included installation of groundwater monitoring wells and a 30-year monitoring program for groundwater and surface water. Monitoring is ongoing.
EPA is currently preparing the fifth five year review for the site. Plans are complete this report before the end of September 2017.
EPA’s Involvement at the Site
Industrial waste sludges were deposited in on-site pits in the early 1950s. In 1961, the site flooded due to Hurricane Carla, possibly causing a fish kill in Clear Lake.
Activity and Use Limitations
At this site, activity and use limitations that EPA calls institutional controls are in place. Institutional controls play an important role in site remedies because they reduce exposure to contamination by limiting land or resource use. They also guide human behavior. For instance, zoning restrictions prevent land uses – such as residential uses – that are not consistent with the level of cleanup.
For more background, see Institutional Controls.
State Contact (TCEQ): Sherell Heidt, 713-767-3708, Sherell.Heidt@tceq.texas.gov
Emergency Response and Removal
Site cleanup has also included removal actions, or short-term cleanups, to address immediate threats to human health and the environment. In May 1984, EPA constructed a fence around the pit to prevent further illegal dumping and to protect monitoring wells from vandalism. In July and August 1985, EPA repaired the fence and posted warning signs.
During cleanup, a site can be divided into a number of distinct areas depending on its complexity. These areas, called operable units (OUs), may address geographic areas, specific problems, or areas where a specific action is required. Examples of typical operable units include construction of a groundwater pump and treatment system or construction of a cap over a landfill.