Clean Air: Looking Beyond the Visible

Dust is only one of the air pollutants that may be government regulated.

By Russell Ellis
Russell Ellis is the Regional Environmental Manager for Hanson Building Products America and a member of NPCA’s Safety, Health & Environmental Committee.

If asked to discuss significant environmental issues facing precast concrete plants, the average plant worker would likely describe the most visible, most obvious pollutant: dust.

Dust, otherwise known as particulate matter, or PM, is a heavily regulated pollutant in the United States and abroad. Point sources of PM, such as weigh hoppers, mixers, silos, conveyors and drop points, are commonly controlled by fabric filters, enclosures, water sprays or moist, raw materials. Fugitive or non-point sources of PM, such as raw material stockpiles, yard dust and roadway dust, are usually controlled by sprinklers, water trucks or some form of chemical dust suppressant.

These types of specific “best available control technologies” are nothing new to the industry or its workforce, but are they enough? What other airborne pollutants are wafting around in a typical precast plant that workers might be breathing?

It is often easy to overlook these hazards. This may be because of a lack of knowledge or understanding of the many types of regulated pollutants, complacency or even the lack of a plan or systems to monitor plant changes that can impact air emissions. Whatever the reason for any such environmental management pitfalls, the important thing to know is that you may be required to have an air permit on file at the local, state or federal level.

Regulated air pollutants
In order to identify the types of precast industry activities that might create emissions other than PM, we must understand the different types of pollutants that are regulated and that might need to be in a facility’s air permit. The U.S. Environmental Protection Agency (EPA) regulates six criteria pollutants: Particulate Matter (PM); Particulate Matter less than 10 microns in diameter (PM-10); Nitrogen Oxide (NOx); Carbon Monoxide (CO); Volatile Organic Compounds (VOCs); and Sulfur Dioxide (SO2). The EPA also regulates chemicals known as Hazardous Air Pollutants (HAPs), which include a list of chemical compounds that have been determined to cause adverse health effects and/or atmospheric reactions at emission levels even less than that of the six criteria pollutants. HAPs are a subcategory of VOCs, and in general terms can be thought of as the most health-impacting types of VOCs. States are mandated by EPA to permit and enforce compliance of these criteria pollutants and HAPs up to certain emission levels. With this delegation, each state has its own rules for what triggers the need for air permits associated with specific industrial activities. Some states require permits for every emission no matter the amount, and others have low-level cutoffs or exemptions that industrial activities must exceed before needing a permit. It is the responsibility of plant and company officials to acquire professional help, as needed, to determine these levels. We must assume that any emission requires a permit, unless it is determined otherwise. In cases where emissions or emissions potential exceed designated levels, plant-wide activities must be regulated by EPA under a federal Title V Major Source Permit.

Targeting industry emissions
Table 1 describes activities common within the industry. The table is not meant to represent an exclusive list of activities or pollutants, but it highlights activities that can generate emissions other than those created from the production of concrete.

Table 1:

Discovering a plant’s emissions potential
Certainly all precast concrete plants do not perform each of the activities listed in the table. However, as a whole, these are all very common activities within the industry.

Knowing this, there is a systematic way to audit a plant’s activities to determine if all permitting needs have been met. The key information required for this process can be pieced together from a variety of sources, including chemical manufacturers equipment manufacturers and plant usage records, among other things. Always look at the MSDS for a chemical to find its chemical properties, such as VOC content – every plant is required by the OSHA Hazard Communication standards to have an MSDS for each chemical on site. However, realize that the exact VOC content is not a legal requirement for an MSDS, so it is not uncommon for this information to be excluded from a particular MSDS – you may have to call the manufacturer to obtain this important information. Depending on your perceived exposure to regulatory risk, it may be a good idea to seek protection under your state’s environmental audit privilege act during the audit/discovery period. Regardless if the audit/discovery method chosen utilizes such state programs where they are offered, help and direction from an experienced environmental consultant or attorney makes good sense. Air permit work is a very technical process that most individuals should not perform alone.