Lots of bad things can happen over 82 years of operating a refinery.  For its first 31 years of manufacturing, regulation was pretty much absent, so there are a lot of unknowns. However, this is what we do know:

• There was a 20 acre landfill onsite containing leaded gasoline and waste oil sludge, as well as reactor catalysts. We do not know how long that landfill was utilized, how much waste was dumped there, nor how waste was contained.
• 20+ ft of petroleum product (fuel) is beneath the site floating on the shallow aquifer; estimated quantity in 1989 was 1.98 million gallons of product.
• 2.6+ million gallons of petroleum product has been recovered from the shallow aquifer. That's a lot of spilled petroleum!

Groundwater investigation at Valero dates back to June 1984, when Mapco Petroleum contracted Engineering Enterprises, Inc. and began remediation of petroleum hydrocarbons spilled onsite.

In May 1991, the EPA paid the site a visit to investigate. During that initial investigation, records indicate that a series of groundwater, surface water, soil , and produce samples were taken. An exchange of concerning letters between involved parties indicates that they used Martin Luther King Jr. Park as a command post and decontamination station, potentially contaminating the public park while they were handling samples of contaminated materials. Coincidentally, unverified reports indicate that the City of Memphis sold a portion of the park to Valero for parking in the 1990s. The southernmost parking lot of the park is, indeed, carved out as a separate parcel of the larger park, though it is currently owned by the City of Memphis and a property sales history has not been found.

On February 4, 1998, a Remediation Order was signed between TDEC and Mapco Petroleum, Inc. That order  included variety of remediation systems onsite. For example, there are at least 9 groundwater recovery wells in the shallow aquifer in the center of the facility. Those wells pump contaminated groundwater, treat it, and release it into their wastewater treatment system.

Remediation systems are also located in the easternmost portion of the facility, south of the bottom-loading truck terminal, in the southwest corner of the refinery, in their wastewater line, and in a manual, portable system. Monitoring and remediation onsite continues to this day, while Valero continues to manufacture oil products.

In addition to the spills and leaks, Valero had numerous flare events, including the two most recent events in February 2021 during a deep freeze in Memphis and July 2023. Gas Flaring is a practice that oil refineries use to burn off excess gas for operational, safety, or economic reasons. Not only is it wasteful, but it has major environmental impacts, contributing to air pollution and the greenhouse effect.

The February 2021 flare misted oil into Nonconnah Creek, released toxic gases in small amounts into the air and lit up the sky as Memphis was blanketed in snow. Downtown residents took video of the flares and posted online. Valero attributed the flaring to the cold temperatures. “Due to the extreme cold weather, operational conditions at the Valero Memphis Refinery are requiring the use of the safety flare system to safely burn off excess material and minimize potential emissions. No community impacts are anticipated.”

The July 2023 flare was due to a series of power surges and outages experience towards the end of the month. The outages caused the flare system to engage as designed and release sulfur dioxide to the atmosphere. Information about the flare event can be found here.