MDI Exposure in Bed Lining Operations

The National Institute for Occupational Safety and Health (NIOSH) has issued a health and safety alert concerning spray-on pick-up truck bed liners.  The alert focused on worker exposure to methylenebis phenyl isocyanate (MDI) and other isocyanates that are frequently found in coatings sprayed on truck beds (but not in all coatings).  NIOSH indicates that overexposure can result in asthma and eye, nose, and throat irritations or serious burns.   SEMA urges members to download the NIOSH alert and recommendations:

OSHA Already Regulates Isocyanates

Isocyanates are already regulated as hazardous air contaminants by OSHA.  OSHA has promulgated permissible exposure limits of 0.02 parts per million (ppm) over a 15-minute ceiling for MDI and toluene diisocyanate (TDI).  Individual states can also establish a more stringent exposure limits.  In fact, California regulates hexamethylene di-isocyanate (HDI) [0.005 ppm/8-hour], and NIOSH has recommended that OSHA do so as well.

The chemicals are found in a wide variety of paints, varnishes, elastomers, and spray on foams, fibers and coatings.  However, since the bed liner industry has blossomed in recent years, OSHA’s regulatory oversight may not be common knowledge.

OSHA Regulations

A number of OSHA regulations are triggered when employers use these chemicals.  OSHA has created webpages with background information.  The following are the main issues and obligations:

Additional Online OSHA Resources Publications:

OSHA Inspection Findings

It is estimated that there are over 2,000 spray-on bed liner franchises nationwide, with about 10,000 workers.  Most businesses employ 6 workers or fewer.  An OSHA sampling of 132 inspections during a one-year period from 2004-05 found that 46% of the operations exceeded the permissible limit of 0.2 milligrams per cubic meter of air for MDI.  Many of the operations had improper: ventilation, respiratory protection, personal protective equipment, and hazard communications.  OSHA found that fairly minimal changes were needed to bring the operations into compliance, such as having a ventilated spray booth.  For example, it may be possible to create a ventilation system by drawing off a supply of air from the facility's existing heating and cooling system and directing it through duct work to the spray area.

OSHA Recommendations

OHSA has recommended several control measures to specifically address MDI exposure issues in bed lining operations, including:

  •     Conduct all spray operations inside a ventilated paint spray booth;
  •     Maintain air velocities at a minimum of 100 feet per minute in the booth;
  •     Utilize local exhaust ventilation when spraying in dead air spaces;
  •     Keep operators outside of the truck bed during spraying;
  •     Use a spray extension handle to keep the nozzle away from the breathing zone;
  •     Set the spray pressure and temperature to the minimum level needed;
  •     Wear a face shield or goggles when half mask respirators are used;
  •     Wear gloves and coveralls when prepping, spraying, and cleaning up; and
  •     Use tools such as spatulas when mixing the materials.

OSHA Seminar on MDI Exposure

The Light-Truck Accessory Alliance, a SEMA council comprised of light-truck accessory manufacturers, distributors, retailers and installers, presented a seminar at the 2006 SEMA Off-Road Show in Indianapolis entitled "OSHA: Hidden Dangers/Hidden Costs: Facts Every Business Should Know."  The seminar included an overview on MDI exposure.  Click here to download a copy of the PowerPoint presentation (3 MB).

OSHA Consultations and Small Business Considerations

Companies using isocyanates should consider having an OSHA audit performed by a qualified consultant to make sure they are in compliance.  They should also speak with their insurance agent, the fire department, etc., to make sure appropriate individuals/agencies are aware of the onsite chemicals.  OSHA has also established a Small Business Outreach Training Program that, among other things, posts a lot of useful information and guides.

Business owners who are concerned about the cost of private professional help (OSHA consultants) can contact the OSHA Consultation Project Office in their state for free consultation service.  Priority is given to businesses with fewer than 250 employees at a worksite, with further consideration given to the severity of the worksite problem. There is a 4 to 6 month backlog so one should make an appointment as soon as possible.  The Consultation Program can help employers evaluate and prevent hazardous conditions in their workplace that can cause injuries and illnesses, including the hazards associated with spray-on truck bed liners.  For more compliance assistance information, please contact the Office of Small Business Assistance at (202) 693-2213.

Summary and Next Steps

NIOSH has issued warnings about exposure to isocyanates for at least a decade, if not longer.  For example, automobile spray painting operations encounter the same issues, although the chemical concentration of isocyanates is lower.  Some of OSHA’s regional offices have simultaneously embarked on a mission to educate the industry on its obligation to properly control the chemicals.

SEMA staff has been in communication with the NIOSH researchers preparing the alert.  SEMA noted that it could be an advocate for and a bridge to the bed liner industry.  Toward this end, SEMA expressed the need to treat the industry with small business consideration, to provide user friendly information and directives, etc.

SEMA staff has also been in communication with OSHA, expressing the need to help bring the industry into compliance without imposition of penalties.  OSHA’s small business consultation is a separate program from OSHA enforcement.  Companies that take advantage of this program should not incur penalties unless they refuse to implement the recommended best practices following a site visit.  Companies that wait for OSHA enforcement to visit the site risk penalties.

For more information, contact Stuart Gosswein at


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