Part 1 looks at how poor indoor air quality (IAQ) can negatively impact productivity, product quality, and worker health. Part 2 will cover IAQ mitigation options and the benefits of implementing a qualified, well-designed system.

Lots of people love that fabulous new car aroma – but the processes that go into manufacturing automotive parts rarely smell so sweet. Automotive manufacturing can be a pretty dirty business. Welding, cutting, grinding, and machining processes all produce toxic particulates that lead to poor indoor air quality (IAQ) if not controlled. Working with plastics, rubber, vinyl, and insulation can also create air quality problems.

Each automotive manufacturing process has exposure risks, regulatory requirements, and mitigation challenges. Failing to control IAQ problems can hurt companies in many ways – some obvious, some less so.

Automotive manufacturers must comply with U.S. Occupational Safety and Health Administration (OSHA) air quality regulations or applicable regional/local regulations. Regulators set maximum permissible exposure limits (PELs) for compounds and elements released into the air during manufacturing. Companies with exposure levels that exceed PELs can be fined.

However, the costs of poor air quality go beyond regulatory repercussions. Failure to control fumes and particulates can harm:

  • Worker productivity: OSHA estimates that poor IAQ causes 6 lost workdays per year for every 10 employees. Resulting worker absences and reduced efficiency cost U.S. companies $15 billion annually.

  • Retention, recruiting: Manufacturers anticipate a shortage of 2 million skilled workers by 2025, according to The Manufacturing Institute and Deloitte. The work environment, including IAQ, matters. Companies recruiting welders and other skilled tradespeople will find that a clean environment will lower turnover and improve recruiting.

  • Product quality: Uncontrolled particulates can permeate sensitive areas such as paint lines or electronic components.

  • Combustion risks: Some dust types are highly combustible, including aluminum, steel, fiberglass, and plastic. These dusts have Kst ratings (a measure of combustibility) 10x greater than wood, making them extremely dangerous if allowed to accumulate in the air.

The most serious problem faced by companies with uncontrolled fumes and dust are risks to worker health and safety. Different processes produce different kinds and levels of particulates, giving each process its own exposure risk profile.

IAQ risk by process

Welding – Manual and robotic welding produce fumes and smoke with widely varying characteristics. The toxicity and volume of fumes generated depend on three variables:
  • Type of welding
  • Materials (base, filler metals)
  • Composition of welding rod/wire

Weld fumes can contain toxic elements and compounds, including nickel, copper, vanadium, molybdenum, zinc, and beryllium. Fumes, made up of tiny particles that are inhaled deeply into the lungs, can have immediate and long-term impacts on worker health. Acute effects can include shortness of breath and respiratory irritation; eye, nose or throat irritation; or nausea. Long-term exposure to hexavalent chromium (hex chrome), manganese, and other elements can lead to chronic or deadly effects.

  • Hex chrome fumes are generated from elemental chrome found in welding consumables, typically when welding stainless steel or other chromium-containing alloys. Overexposure to hex chrome can cause asthma, eye irritation and damage, and ear drum perforation. A carcinogen, hex chrome is associated with elevated rates of cancer.

  • Manganese is found in virtually all types of welding wire and many base materials. When heated, it reacts with oxygen to form toxic, combustible fumes. Chronic manganese exposure can cause neurological damage (called manganism) that mimics multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), or Parkinson’s disease.

  • Weld fume overexposure can also cause a serious condition called metal fume fever or welding sickness. Metal fume fever causes non-specific, flu-like symptoms such as fever, chills, nausea, headache, muscle or joint pain, shortness of breath, and fatigue. With continued overexposure, the illness can progress to shock or convulsions, requiring immediate medical attention.

  • Aluminum welding produces magnesium oxide and aluminum oxide, both of which cause respiratory irritation. The filler metals used for welding aluminum components tend to be less dangerous than those used for welding steel, but breathing aluminum fumes is still dangerous. Long-term overexposure is associated with neurological effects, including cognitive impairments, peripheral neuropathy, and motor dysfunction.

  • Machining – Manufacturing engine blocks and other drivetrain components often involves precision machining. Machining lubricants create fine oil mists that can be invisible. As the mists settle, they can create slip-and-fall hazards for personnel. They also have health impacts when inhaled: depending on the size of the particulates and the chemistry of the lubricant, extended exposure may lead to asthma, chronic bronchitis, chronically impaired lung function, fibrosis of the lung, and cancer. Metalworking fluids can also become contaminated with disease-causing pathogens.

    Cutting, grinding – Larger particulates from cutting and grinding don’t make their way as deeply into the lungs as the fumed particulates from welding, but the large volume of dust produced by these applications present special hazards. Fiberglass, metal, glass, plastics, and epoxy resins can all cause respiratory irritation; some materials are also carcinogenic when inhaled. Newer materials used in the automotive industry, including carbon fiber and composites, are associated with skin and respiratory irritation, contact dermatitis, and chronic interstitial lung disease.

    Plastics – Molding cup holders, air conditioner vents, dashboards, and other plastic components creates its own set of health and safety challenges. Polymers and resins generate volatile organic compounds (VOCs) when heated during thermoplastic injection molding. The toxicity of the emissions depends on the type of plastic being processed. Polyvinyl chloride (PVC) can produce hydrochloric acid gas, while acetyl plastics produce formaldehyde. Many of these chemicals are associated with long-term health risks – respiratory problems, central nervous system effects, and cancer – and some present an immediate asphyxiation risk of not controlled. Workers may also be exposed to plastic dusts when handling raw materials, which may come in the form of powders or pellets.

    Rubber manufacturing – Like plastic manufacturing, rubber processing produces volatile emissions that can be toxic with overexposure. Breathing in fumes from rubber processing is associated with cancers of the bladder, stomach, and lungs, in addition to chronic respiratory problems, skin disorders, and possibly reproductive effects.

    Better IAQ

    There are steps that you can take to ensure that your facility not only meets minimum regulatory requirements but, is prepared for any future changes. Meeting current OSHA PELs is a necessary start. However, many automotive companies are moving toward stricter internal standards for IAQ to meet productivity and sustainability goals. The American Conference of Governmental Industrial Hygienists (ACGIH) has developed voluntary exposure guidelines based on rigorous science, which are rapidly becoming internationally recognized best practice for the manufacturing industry.

    A well-designed air quality system can protect companies from legal liability and government fines, and sanctions while improving worker health, satisfaction, and productivity. A qualified air quality system designer can help automotive companies find solutions that balance costs, regulations, and goals. We’ll take a closer look at the mitigation options in our next IAQ article.


    About the author: Craig Widtfeldt is the executive technical director at RoboVent. He can be reached at 614.498.1796 or