Narcogun CR-346 NN Spray-Applied Fireproofing

Product Description

Narcogun CR-346 NN was a spray-applied fireproofing material manufactured by Narco and marketed for use in commercial, industrial, and institutional construction projects. Produced from approximately 1966 through the early 1980s, the product was designed to provide passive fire resistance to structural steel, decking, and other building components by forming an insulating barrier that could slow the spread of heat and delay structural failure during a fire event.

Spray-applied fireproofing products of this type were widely used throughout this period on construction projects ranging from high-rise office buildings and manufacturing facilities to warehouses and public infrastructure. The application method—pneumatically spraying a wet or semi-dry mixture onto steel members and structural surfaces—was a standard technique embraced by the construction industry for its speed and coverage capability. Narcogun CR-346 NN was positioned within this segment of the market as an efficient solution for satisfying fire-resistance requirements established by building codes and insurance underwriters of the era.

Production of the product ceased in the early 1980s, a period that corresponded broadly with increasing regulatory pressure on asbestos-containing building materials. The U.S. Environmental Protection Agency’s eventual prohibitions and restrictions on sprayed asbestos-containing materials, along with mounting litigation, contributed to the withdrawal of products like Narcogun CR-346 NN from the marketplace.

Asbestos Content

Narcogun CR-346 NN contained chrysotile asbestos as a component of its formulation. Chrysotile, sometimes referred to as white asbestos, is a serpentine-form fiber that was the most commercially prevalent asbestos variety used in building products throughout the mid-twentieth century. Its fibrous structure provided tensile reinforcement and enhanced the thermal insulating properties that made fireproofing materials effective.

In spray-applied fireproofing products, chrysotile asbestos fibers were typically blended with binders and other mineral components to produce a mixture that adhered to structural surfaces and hardened into a cohesive, fire-resistant coating. The asbestos content in products of this category could represent a substantial portion of the dry mixture by weight, meaning that the total fiber mass applied to a given structure could be considerable.

Chrysotile asbestos is classified as a known human carcinogen by the International Agency for Research on Cancer (IARC) and is regulated as a hazardous substance under the Occupational Safety and Health Administration (OSHA) asbestos standards, codified at 29 C.F.R. § 1910.1001 (general industry) and 29 C.F.R. § 1926.1101 (construction). The Asbestos Hazard Emergency Response Act (AHERA) further identifies sprayed-on asbestos-containing materials in buildings as a category of friable material warranting specific inspection, management, and abatement requirements.

Friability is a key concern with spray-applied fireproofing. Once cured on structural surfaces, these coatings can be disturbed by routine maintenance, renovation, mechanical impact, or building vibration, releasing respirable asbestos fibers into the air without any specialized intervention.

How Workers Were Exposed

Industrial workers and construction tradespeople working on job sites where Narcogun CR-346 NN was applied or subsequently disturbed faced potential exposure to airborne chrysotile asbestos fibers. Exposure pathways associated with spray-applied fireproofing products generally fall into two broad phases: application-era exposure and post-installation disturbance exposure.

During the application phase, workers operating pneumatic spray equipment mixed, loaded, and discharged the material directly. The spraying process itself could generate a visible plume of particulate matter, including respirable asbestos fibers, in the immediate work area. Workers nearby—including other tradespeople such as ironworkers, electricians, and pipefitters whose tasks brought them into the same work zones—could inhale fibers without necessarily performing the spray operation themselves.

After installation, the cured fireproofing remained in place on structural members throughout the lifespan of affected buildings. Industrial workers engaged in maintenance, repair, or modification of equipment, piping, electrical systems, or structural components in buildings where this product had been applied could disturb the coating through physical contact, vibration, or nearby cutting and drilling operations. Such secondary or bystander exposure is a recognized mechanism of asbestos-related disease documented in occupational health literature and regulatory guidance.

OSHA’s permissible exposure limit (PEL) for asbestos is 0.1 fibers per cubic centimeter (f/cc) as an eight-hour time-weighted average, with an excursion limit of 1.0 f/cc averaged over a thirty-minute period. Spray application of asbestos-containing materials in the absence of engineering controls, respiratory protection, and containment procedures—conditions common on job sites during the 1960s and 1970s—could produce airborne fiber concentrations substantially in excess of these limits.

Diseases associated with occupational asbestos exposure include mesothelioma, asbestos-related lung cancer, asbestosis, and pleural abnormalities including pleural plaques and pleural thickening. Mesothelioma, a malignancy of the lining of the lungs, abdomen, or heart, is considered a sentinel disease for asbestos exposure due to its strong and specific etiological link to asbestos fiber inhalation.

Narcogun CR-346 NN is classified as a Tier 2 product for the purposes of this reference. No dedicated asbestos bankruptcy trust fund has been established by Narco specifically to compensate individuals injured by this product. Compensation for individuals harmed by exposure to this product has been pursued through civil litigation in the tort system.

Litigation records document claims brought by plaintiffs who alleged occupational exposure to Narcogun CR-346 NN and subsequently developed asbestos-related diseases including mesothelioma and lung cancer. Plaintiffs alleged that Narco and, in many cases, related defendants including distributors, contractors, and premises owners, were liable for injuries arising from exposure to the product’s asbestos content. Plaintiffs alleged that manufacturers of asbestos-containing spray fireproofing products were aware of the hazards associated with asbestos inhalation and failed to adequately warn workers or take steps to prevent harmful exposures.

Individuals who believe they were exposed to Narcogun CR-346 NN and have been diagnosed with an asbestos-related disease should consult with an attorney experienced in asbestos litigation. Key information relevant to any potential claim includes:

  • Diagnosis documentation: Medical records confirming an asbestos-related condition such as mesothelioma, lung cancer with asbestos exposure history, asbestosis, or pleural disease
  • Work history: Detailed employment records identifying job sites, employers, dates of work, and trades performed in areas where spray fireproofing was applied or disturbed
  • Product identification: Co-worker testimony, job site records, purchasing documents, or other evidence linking Narcogun CR-346 NN specifically to a work location

Statutes of limitations for asbestos claims vary by state and typically begin to run from the date of diagnosis or the date on which the claimant knew or reasonably should have known of the connection between their illness and asbestos exposure. Prompt consultation with qualified legal counsel is advisable to preserve claim rights.

Because no trust fund is available for this product, any financial recovery would be pursued through direct litigation against potentially responsible parties. The viability and value of such claims depend on the specific facts of each individual’s exposure history, medical condition, and applicable state law.