Lead Problems in Gray Iron Foundries

Abstract

In order to determine whether or not potentially hazardous lead concentrations are present in gray iron foundry processing and employee's breathing zone, the lead concentrations were determined at various locations within several foundries. The foundries used in this study were limited to those that use crushed engine blocks in their feedstock. In addition, the possible sources of the airborne lead were investigated. The investigation was conducted to determine the type of scrap material used in the feedstock. The composition of the feedstock does not change from foundry to foundry, the only variable would be the type of scrap metal being used. The feedstock consists of pig iron, steel plate, reclaimed risers and sprues, and scrap.

The engine block material was returned to the laboratory to be acid washed for determination of lead. The results of the leading showed that scrap containing carbon residue were found to contain the highest lead values, 14.71 mg/mL.

Since the gray iron foundry industry uses electric melt and cupola melt as the primary melting sources, a determination was made to evaluate lead levels at those facilities. Personal exposure results for cupola melt foundry show the transfer ladle operator exposure to lead to be 0.11 mg/m3, cupola tender 0.08 mg/m3, iron pourers exposure average was 0.06 mg/m3, and the cupola chargers' exposure averaged 0.05mg/m3. Personal samples collected in the electric melt foundry showed the highest exposure to the furnace operator, as large as 1.44 mg/m3, furnace charger 1.14 mg/m3, bull ladle operator 0.22 mg/m3 and iron pourers 0.33 mg/m3.

The results of the airborne lead sampling indicate that the gray iron foundry industry, which processes scrap engine material, has a potentially serious health problem. This problem is occurring during the melting and pouring of molten metal. The results of the personal exposures indicate a serious violation of the present OSHA standard for lead.

A source of lead, which may not be readily recognized in the reclaiming of old engines, is leaded gasoline. Upon remelting the scrap, the lead residue found on the engine block material, is boiled off and releases lead fumes into the breaking zone of the employees.

This work demonstrated that the procedures outlined in this thesis are reliable and reproducible for the determination of lead in feedstock material. The results of personal exposure sampling show that employees working in gray iron foundries using scrap engine block material are exposed to excessive amounts of lead. Lead his been detected in other kinds of feedstocks for foundries. Studies similar to the ones done here are very much needed as potentially serious health hazards may exist at foundries that use those various feedstock.