Silica Case Studies Needed on Technological Feasibility of New Standard

Issue:  AFS, NAM, and our legal team have a meeting scheduled on Aug 23 with OSHA on the silica rule.  WE NEED YOUR HELP! 

AFS is in need of brief case studies that highlight the difficulty of meeting OSHA’s new silica standard that we can utilize in our meeting.  The information needed centers on technological feasibility for several different foundry processes (See list below). 

These would be anonymous reports that would briefly summarize situations, root causes, control efforts, and results along with key demographic information (e.g. type of foundry, metals, casting  size, number of employees).   They might be only two or three paragraphs long.  Cost information would also be helpful.  The point is to show that it is often difficult to reach the PEL consistently, even with diligent control efforts.  Also note if you have agreements in place with OSHA that allows you to utilize respirators in these areas. (See attached examples)


 It would be extremely helpful to have information for each of these activities demonstrating:

  1. Engineering controls are being examined and there is still significant uncertainty as to whether the PEL can be met, or
  2. If the PEL can be met (or the companies can get close to the PEL), there is a significant cost to do so and it could involve major overhauls of how the work is performed. 

 Foundry Processes:  Molder, Coremaker, Furnace Operator, Shakeout Operator, Knockout Operator, and Cleaning/Finishing Operator

We would really appreciate your help on this important next step with DOL/OSHA. 




Stephanie Salmon l Vice President Government Affairs l American Foundry Society – Washington Office

25 Massachusetts Ave, NW - Suite 800 l Washington, D.C. 20001

Ofc:  202-452-7135

Example 1

Silica Compliance Case Study – Grinding


Foundry Information

Metal Cast: Ductile iron

Mold type: Green Sand

Size of Foundry: 200 Employees total

Size of operation: 10 employees

Process: Finishing (Grinding)

Employees pick up 5 to 20 pound iron castings from a conveyor and grind off undesired metal before dropping the finished casting into a chute to the floor below.  Castings have been precleaned in an abrasive blasting machine.  Grinding is performed on one of 12 stand grinder with 24 inch grinding wheels. 

Control Efforts and Results

Grinding wheels are enclosed and each grinder has good ventilation.  Grinding wheel enclosure has been improved to minimize open areas.  Exhaust has been improved to over 1200 CFM.  Grinding room is enclosed and ventilated.  Air supplied helmets are used by all grinders (for eye protection and cooling as well as respiratory protection).  Exposures outside the air supplied hood exceed the old silica PEL.  Exposures inside the hoods are not detectable or below the action level.  No additional controls are feasible and employees would refuse to give up the air supplied hoods anyway.   

Example 2

Silica Compliance Case Study - Knockoff

Issue:  Areas in foundries where most challenged in meeting current 100 µg/m3 PEL and new lower PEL of 50 µg/m3 with an action level of 25 µg/m3.

Foundry Information

Metal Cast: Ductile iron

Mold type: Green Sand

Number of Employees: 200

Process: De-spruing (knockout)

Employees (2-4) remove sprues from castings that have come out of shakeout and travel along a vibrating conveyor.  Employees use hammers and hydraulic spreaders to separate sprues, directing parts to one side of the conveyor and sprues to another.

Control Efforts and Results

Ventilation installed on the opposite side of the vibrating shaker and has been reworked several times to achieve maximum effectiveness.  Hydraulic spreaders were installed to reduce dust and improve ergonomics.  Makeup air directed from directly behind workers to the exhaust on the other side of the conveyor.  Makeup air reconfigured to create clean air islands at worker positions.  Electrostatic misters tried with poor dust control and even worse product and housekeeping issues.  After OSHA citation, Salt Lake City experts reviewed the process.  Exposures remain above the old PEL most of the time. Respirators accepted as abatement measure. Air supplied respirators are worn by the knockout operators. 

Posted in AFS National.