Foundry Sand Additive

A foundry sand additive is any material mixed into molding or core sand at a metal-casting foundry to improve how the sand holds shape, releases gases, or withstands heat from molten metal. Historically, some of these additives contained asbestos fibers, most often chrysotile, to add heat resistance and reinforcement. Workers who handled, mixed, or breathed dust from these sands could inhale asbestos fibers released during molding, shakeout, and cleanup.

Origin

The term comes from "foundry," a workplace that casts metal, and "additive," any substance added to improve a base material. Asbestos-containing foundry additives were marketed from at least the 1930s through the 1970s under brand names sold by companies supplying the steel, iron, and non-ferrous casting industries.

Significance in Asbestos Context

For patients who worked in foundries (as molders, coremakers, shakeout workers, grinders, or laborers), foundry sand additives are an often-overlooked source of asbestos exposure. Because the asbestos was blended into sand and then heated by molten metal, fibers could be released during mixing, mold-making, the violent "shakeout" stage when castings were knocked free, and during sweeping and bag-handling. Establishing this exposure pathway matters because foundries usually had many asbestos sources at once (insulation, gaskets, protective clothing, furnace linings), and identifying the additive products by brand name can connect a case to specific manufacturers. Defendants frequently argue that foundry exposures were too brief or too dilute to matter; your experts will need to characterize the dust-generating tasks, the products used, and the fiber type released to rebut that.

Example Sentence

His industrial hygiene expert traced part of his exposure to a chrysotile-containing foundry sand additive that was poured into the muller every shift during the years he worked the core room.

Related Terms

Chrysotile, Occupational Exposure, Bystander Exposure, Product Identification, Industrial Hygiene, Shakeout

Notes

• Try to recall and write down brand names of bagged additives, parting compounds, core binders, and mold dressings used at the foundry. Product identification is often the key to naming defendants.
• List every job task you performed (mixing, mulling, ramming, shakeout, grinding, sweeping, bag dumping) and approximate frequency; dust generation varies sharply by task.
• Identify co-workers who may remember the product names and suppliers, and preserve any old purchase orders, MSDS sheets, or union records if available.
• Tell your treating physician and any medical-legal expert about foundry work specifically, even if you also had shipyard, construction, or military exposures. Foundry exposure is frequently missed on standard occupational history forms.