Vital Materials Ltd is the world's leading manufacturer of selenium and tellurium products as well as being a key producer of gallium, indium, germanium, bismuth, and cadmium products for diverse end markets and hi-tech applications including semiconductors, displays, electronics, photovoltaics, LED, infrared materials, acousto-optics, thermoelectrics, photosensors, radiation detectors, pharmaceuticals, feed additives, glass, ceramics, and metallurgy.
SAK Environmental LLC provided U.S. based environmental services to its local division, Phoenix Infrared, who's Zinc-Selenium (ZnSe)operations were being relocated back to China. Years of manufaturing had visibly (and invisibly) contaminated both the entire building and equipment with Zinc-Selenide dust which visibly is light-yellow. Both Zinc and Selenium are regulated heavy metals for their toxicity with Selenium a USEPA Resource Conservation & Recovery Act (RCRA) regulated metal. THe building had to be cleaned for safe reuse and to fulfill lease requirements, and equipment had to be safe for international shipment.
SAK provided design-build, turnkey servcies that include environmental engineering, industrial hygiene, and waste removal. Specifically, work included cotainerized nwaste inventory and removal, Non-production equipment removal, Production-related surface decontamination,partial demolition of interior walls to access and demobilize large reactors, and project monitoring and reporting.
To make sure the building was safely decontaminated, three zinc selenide performance standards were developed based on the likelihood that a future worker would be exposed to the surface: Touchable; Reachable; and, Un-reachable.
The performance standard for Touchable Surfaces was developed to be the most stringent of the three performance standards because these are surfaces a future worker was most likely to come into contact, and was developed using the OSHA Technical Manual and the NIOSH guide Threshold Limit Value (TLV) for selenium for indoor air of 0.2 milligrams per cubic meter (mg/m3). Surface wipe sampling and laboratory analysis was conducted to verify that cleaned surfaces met this standard. Samples were collected using laboratory provided ghost wipes where SAK would swab a 100 square centimeter (cm2) of surface following ASTM 1728-16 “Standard Practice for Collection of Wipe Samples.” A total of 78 wipe samples were analyzed throughout the project and 65 wipe samples used to support compliance with project defined performance standards.
