Health hazard evaluation report: HETA-2003-0237-2986, Morton Metalcraft, Welcome, North Carolina.
On April 25, 2003, the National Institute for Occupational Safety and Health (NIOSH) received a confidential employee request for a health hazard evaluation (HHE) at Morton Metalcraft in Welcome, North Carolina. The request concerned potential exposures to emissions from a plasma cutter. In particular, the plasma cutter produced a dense smoke that was reported to circulate throughout the facility, enhanced by an inadequate ventilation system. Employees associated exposure to the smoke with health problems including sore throat, runny nose, eye irritation, coughing, migraines, and vomiting. On February 25, 2004, an industrial hygienist and medical officer from NIOSH conducted an initial site visit to better understand the facility's processes and procedures and to plan a return site visit to conduct sampling. Before the return site visit, the use of the plasma cutter was discontinued at the facility. Concerns of exposure to welding fumes, however, continued to be expressed, as well as continuing reports of inadequate ventilation, particularly during the winter months when many of the facility's doors and windows are closed. On March 7-10, 2005, a site visit was conducted to perform sampling for welding fumes, including individual metals, carbon monoxide, and ozone. Confidential employee interviews were conducted with a random sample of employees. Exposures to metals in the welding fumes were below applicable occupational exposure limits (OELs). For personal breathing zone (PBZ) and area air samples, the most prominent metal collected was iron. The PBZ samples with the highest airborne concentrations of iron (4.0 milligrams per cubic meter (mg/m3) and 3.7 mg/m3) were less than half of the Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) of 10 mg/m3, but were nearing the NIOSH recommended exposure limit (REL) of 5.0 mg/m3. Time-weighted average (TWA) concentrations of carbon monoxide (CO) were below both the NIOSH REL and the OSHA PEL. Instantaneous readings for ozone did not reveal levels above the NIOSH REL. Confidential interviews did reveal complaints of eye, nose, and throat irritation, with some reported to be work-related. Individuals with symptoms reported welding or working in the vicinity of welding activities as their main job duties. NIOSH investigators determined that no hazard from exposure to metal fumes, CO, and ozone existed at the time of the NIOSH site visit. The sampling results indicated that the employees were not exposed to levels of metals or gases above permissible levels. Eye, nose, and throat irritation, particularly during winter months, were reported during confidential interviews. Included in this report are recommendations for improvements in general ventilation during winter months and in training on hazard communication and use of personal protective equipment.