pah

Thermoset Plastic Manufacturing and PAH Exposure

Thermoset Plastic Manufacturing and PAH Exposure 1

Upon entering the kitchen and flicking on the light, little thought is likely given to where or how that light switch was made, any more than thought is given to the countertops on which the food is prepared or the pot handles of the vessel used to cook the food. Those who work in the thermosetting plastics industry, however, think about these products all the time. It’s what they do.

Plastics are one of the most used and indispensable materials in modern life and thermoset plastics, in particular, are valued for their stain and heat resistance and for their durability.

Employing over 1.1 million workers in the United States, the plastics industry represents a substantial percentage of the American workforce. (1) Of those workers, many of them work in thermosetting, jobs ranging from raw material manufacturing to plastics processing.

Thermoset plastics are synthetic materials that cannot be molded or reheated after their initial heat formation. Thermosetting is the process of transforming granular material into molded shapes, curing through a chemical reaction activated by heat and pressure, which in turn forms a strong molecular bond. This is in contrast to thermoplastics, which are products that soften when heated and harden after cooling.

As with all industries that manufacture goods, there are occupational risks.

One such risk is PAH exposure. PAHs, polycyclic aromatic hydrocarbons, are a group of chemical compounds that are found naturally in the burning of fossil fuels and are by-products of heat-produced manufactured goods such as medicines, dyes and plastics. Of these compounds, naphthalene is a top contender of risk: a substance that is not only pervasive, but also harmful. (2)

The chemical naphthalene is most commonly known for its use in mothballs. Naphthalene evaporates easily and gives mothballs their distinct odor. But in the production of thermosets, naphthalene is released into the air at the melting and burning stage, causing vapors to enter a worker’s air space. Once airborne, naphthalene is broken down by moisture and sunlight but not quickly; often lingering in the atmosphere up to 24 hours. (3)

Acute (short-term) symptoms of naphthalene exposure will present immediately when levels are high. Various symptoms include headache, confusion, nausea, vomiting, abdominal pain, dermatitis, optical twitching and corneal damage. Organs targeted are the eyes, skin, blood, liver, kidneys, and central nervous system. (4) Cataracts have also been reported in workers acutely exposed to naphthalene by inhalation. Chronic (long-term) exposure, especially at low levels, is harder to identify due to symptoms being typical of a variety of other causations. Chronic symptoms are similar to those of acute exposure, with additional indicators such as retinal damage and cataracts. The EPA has classified naphthalene as a possible (Group C) human carcinogen. (5)

But naphthalene exposure to workers in the thermosetting industry is by no means inevitable. Preventative measures on the manufacturing floor – protective clothing, proper ventilation, and indoor air cleaning products – can eliminate the presence of offending vapors and fumes.

At Air Systems Inc, we protect our customers in the plastics industry by providing them with stellar indoor air cleaning equipment and products. Contact us today to set up a free consultation with one of our clean air specialists.

Occupational PAH Exposure to Polycyclic Aromatic Hydrocarbons in the Workplace

Polycyclic Aromatic Hydrocarbons and Poor Indoor Air Quality Threaten Workers in Various Industries

Occupational PAH Exposure To Polycyclic Aromatic Hydrocarbons In The Workplace 1

It’s always unsettling to learn that our day-to-day activities have consequences beyond intent. The warmth emitted from a wood-burning fireplace, a walk around the neighborhood, and a backyard cookout are all enjoyable events. And yet, these seemingly innocuous activities all create an environmental concern. Say hello to polycyclic aromatic hydrocarbons (PAHs).

What Exactly Are Polycylic Aromatic Hydrocarbons?

PAHs are a group of chemicals that contain more than 100 different compounds. (1) These natural substances are released into the air from a variety of actions such as:

  • Burning organic substances like wood
  • Gasoline
  • Charcoal-broiled meat. PAHs produced from these sources can create small airborne particulates or latch on to existing particles, creating air quality contaminants.

These sources can create small airborne particulates or latch on to existing particles, creating air quality contaminants. PAHs are also a natural part of the environment. Most people have been in contact with one or more sources of PAHs over the course of their lifetimes, in some cases, routinely. The National Institutes Of Health summarizes the constant presence of PAHs:

PHAs are released from burning coal, oil, gasoline, trash, tobacco, wood, or other organic substances such as charcoal-broiled meat. They can occur naturally when they are released from forest fires and volcanoes and can [also] be manufactured. Other activities that release PAHs include driving, agricultural burning, roofing, or working with coal tar products, sound- and water-proofing, coating pipes, steelmaking, and paving with asphalt. PAHs are found in the asphalt that covers roads and parking lots and in smoke and soot. They are also found in coal tar – coal tar products are used in medicines for skin diseases, such as psoriasis, and in insecticides, fungicides, and pesticides. Coal tar creosote is widely used for wood preservation. Coal tar and coal tar pitch are used for roofing, road paving, aluminum smelting, and production of coke, a coal residue used as fuel. (1)

PAH Exposure Occurs All Around Us: Where Can It Be Found?

The major route of PAH exposure for the general population is from breathing ambient air, eating food containing PAHs, smoking cigarettes, or inhaling smoke from open fireplaces. Charring meat or barbecuing food over charcoal, wood, or another type of fire greatly increases the concentration of PAHs. Soil also contains PAHs, primarily from airborne fallout. (2) But the greatest concern for PAH exposure exists where most people spend the bulk of their time – at work.

Industries that use or produce tar or asphalt or participate in the burning of fossil fuels routinely emit PAHs, as do any trades that require a running engine (think: mechanics, street vendors). In addition, persons who work in smokehouses, foundries, or trash incineration centers are at risk. As are those involved with metalwork, wood preserving, or chemical production. PAHs are also used to make plastics, dyes, pesticides, and medicines. (3) The businesses affected are varied and numerous.

This widespread potential for occupational PAH exposure is problematic. Unlike casual human exposure – fumes from a fireplace, car exhaust as you walk on the sidewalk, smoke from the occasional backyard cookout – occupational exposure is constant. When a substance is mass-released, as it is within an industrial plant or from a large manufacturing drum, it enters the atmosphere. While the release may not always lead to exposure, often it does.

Health Effects

This widespread potential for occupational PAH exposure is problematic. Unlike casual human exposure – fumes from a fireplace, car exhaust as you walk on the sidewalk, smoke from the occasional backyard cookout – occupational exposure is constant. When a substance is mass-released, as it is within an industrial plant or from a large manufacturing drum, it enters the atmosphere. While the release may not always lead to exposure, often it does.

After polycyclic aromatic hydrocarbons are swallowed, inhaled, or absorbed through the skin, the body converts them into breakdown products and passes them out of the body. (1) But when exposure is constant, as in an indoor, occupational setting, the body cannot excrete them fast enough to rid the body of the toxins. Occupational PAH exposure alone isn’t necessarily enough to cause serious problems. The amount of PAHs, the duration of exposure, as well as individual characteristics such as gender, age, health, lifestyle, etc…, are all factors that affect the degree to which a person is affected.

At this point, it is not clear whether or not PAH exposure can cause short-term health effects, as the other compounds commonly found with PAHs may be the cause of short-term symptoms such as eye irritation, nausea, vomiting, diarrhea, and confusion. But studies have determined that PAHs can – and do – cause long-term, harmful health consequences resulting from occupational exposure. Symptoms can include cataracts, kidney and liver damage, and jaundice. 

While the most severe health risk for PAH exposure is cancer, it more often results in non-carcinogenic effects, mainly concerning pulmonary, gastrointestinal, eye, and skin problems.

Solutions for PAH Exposure: Safe Extraction

Reducing indoor occupational PAHexposure comes by way of protective clothing and safe work practices. But most important is capturing the PAHs at the source, through extraction. For extra protection, an ambient backup system may be employed as a secondary source. Employers who wish to protect themselves and their employees don’t have far to look to find an easy solution.

 serve our customers by providing indoor air quality management solutions in addition to our stellar air cleaning products. Contact us today for a free air quality assessment with one of our skilled and experienced indoor environmental specialists.