When considering pollution exposures associated with chemical facilities, visions of uncontrolled hazardous chemical spills or explosions spewing black smoke and deadly toxins into the air often come to mind. However, virtually any industrial facility can impact the environment, perhaps in less dramatic fashion but with similar catastrophic results. This is especially true of chemical facilities. The exposures involved may not be as obvious as they are for risks such as bulk storage facilities, but every chemical facility needs to consider its pollution exposures and how best to manage them. This article evaluates some of the potential pollution exposures facing chemical facilities. Some are characteristic of specific types of operations, but most apply to any chemical manufacturing or distribution facility. Generally, there are four exposure pathways that need to be considered when evaluating a facility’s potential impact to the environment: air, soil, surface water and groundwater.

Air Exposures

Air exposures are obvious at some facilities with equipment such as distillation towers or chemical reactors and not so obvious at chemical repackagers or distribution facilities. These facilities store bulk chemicals like ammonia on-site, which can be extremely hazardous if released to the atmosphere. Chemical manufacturing facilities generate air emissions throughout the production process from the combustion process, with the actual extent of emissions depending on the control equipment utilized. The process may involve elaborate extraction systems, fractionation systems or simply make use of dip tanks, cleaning solutions, or there may be an in-house lab.

Aboveground storage tanks containing volatile compounds or petroleum products generate fugitive emissions. Government intervention and community awareness are forcing chemical facilities to take more responsibility than ever for their current emissions and accidental releases. These gases present inhalation and explosion hazards if not properly vented or captured. Further, many chemical facilities are equipped with pretreatment systems that have chlorine gas on-site which can be deadly when released.

Soil Exposures

The soils underlying and surrounding a facility are another potential pollution exposure pathway. Prior to the 1980s, many companies deposited all kinds of waste materials into the ground. These ranged from solid filter cake wastes to liquid chemicals and toxic wastes. While the oozing drum is often imagined as the typical culprit in soil contamination, most facilities impact the soils near them in some way. The impact could be from something as simple as the stormwater runoff from the parking lot that carries minor spills of petroleum hydrocarbons into surrounding soils. On the other hand, the impact could be as complex as a release from a paint manufacturer that deposits lead onto the ground of neighboring properties causing severe lead contamination.

In between these scenarios is the potential contamination from any facility that stores materials or waste outside in tanks or drums. Underground storage tanks may leak over time and contaminate the surrounding soil. Aboveground storage tanks can leak from the bottom or rupture, resulting in a catastrophic release. If the tank does not have adequate secondary containment, the soil around the tank will be impacted. In addition, drum storage areas may contain leaking drums that impact soil over time.

Underground piping is another potential source of contamination. If the piping is breached or if structural failure occurs, the pipeline will release its contents into the soil. A fire at a facility is an additional exposure. Chemicals used to extinguish the fire or firewater that becomes contaminated may migrate into on-site and off-site soils. General facility storm water runoff is also an area of concern. Parking lot runoff was previously mentioned, but the runoff from the entire property can carry contaminants from storage areas and production areas into the surrounding soils.

It is difficult, if not impossible, to consider the soil exposure pathway without also taking into consideration the next two exposure pathways: surface water and groundwater. Most impacts to soils will also impact surface water, groundwater or both. For example, in the case of an aboveground tank failure, the materials released may reach a surface water body or, if the soils are not remediated promptly, the underlying groundwater could be affected by a spill. A leaking underground storage tank could also impact the groundwater. In short, any spill at a site has the ability to affect nearby surface water and underlying groundwater.

Surface Water

Many chemical facilities generate effluent from their production processes or wastewater treatment. If the effluent is discharged to a surface water body, the receiving stream is vulnerable to discharges. These discharges may contain elevated levels of contaminants as well as spills from the facility that reach the discharge point via established lines. Manufacturing operations not only have to be concerned with discharges, but also with stormwater runoff that leaves the property via nearby streams or rivers. Stormwater runoff, as mentioned previously, can carry contaminants from the property to these receiving bodies. Sites with any type of on-site loading or unloading operations or bulk storage can also impact surface water via stormwater that has come in contact with these materials.. In addition, fire fighting chemicals or contaminated firewater can also easily migrate to nearby surface water.

Groundwater

Air releases eventually dissipate. Streams will eventually clean themselves once the contamination source has been removed. Contaminated soil is relatively easy to remove or remediate. Groundwater contamination, however, is particularly difficult to characterize and to remediate because anything that reaches soil has the ability to reach groundwater. How long it takes and the extent of the contamination depends on soil type and the geology of the area. Chemical facilities, or any facility that has spilled material or had it leak into or onto the ground, will eventually impact the underlying groundwater. Facilities with tanks and/or storage of any materials or wastes outdoors also need to consider this exposure. Spills or leaks may reach groundwater. Underground piping of any sort can also be a concern. Product, process or waste lines may leak over time or be breached unknowingly and affect groundwater. Sumps under production facilities are additional potential sources of groundwater contamination if their integrity is compromised.