Reducing environmental risk associated with laboratory decommissioning and property transfer

The need for more or less space is a common laboratory problem. Solutions may include renovating existing space, leaving or demolishing old space, or acquiring new space or property for building. All of these options carry potential environmental risk. Such risk can be the result of activities related to the laboratory facility or property (e.g., asbestos, underground storage tanks, lead paint), or the research associated with it (e.g., radioactive, microbiological, and chemical contamination). Regardless of the option chosen to solve the space problem, the potential environmental risk must be mitigated and the laboratory space and/or property must be decommissioned or rendered safe prior to any renovation, demolition, or property transfer activities. Not mitigating the environmental risk through a decommissioning process can incur significant financial liability for any costs associated with future decommissioning cleanup activities. Out of necessity, a functioning system, environmental due diligence auditing, has evolved over time to assess environmental risk and reduce associated financial liability. This system involves a 4-phase approach to identify, document, manage, and clean up areas of environmental concern or liability, including contamination. Environmental due diligence auditing includes a) historical site assessment, b) characterization assessment, c) remedial effort and d) final status survey. General practice standards from the American Society for Testing and Materials are available for conducting the first two phases. However, standards have not yet been developed for conducting the third and final phases of the environmental due diligence auditing process. Individuals involved in laboratory decommissioning work in the biomedical research industry consider this a key weakness.

Exposure assessment of laboratory students

The Massachusetts Institute of Technology (MIT) has two kinds of laboratories, teaching for undergraduate students and research laboratories for graduate students and research staff. The objective of this study is to determine chemical exposures during teaching and research activities. There are three hypotheses in this study: (1) Exposures in academic laboratories are well below health standards; (2) Students in undergraduate teaching laboratories have less chemical exposure compared to students in graduate research laboratories; and (3) Students in different disciplines are expected to have different exposures. From September 1996 to December 1996, 132 air samples were collected from both teaching and research laboratories in the departments of Material Sciences and Engineering, Chemical Engineering, and Biology. The most frequently sampled chemicals in these three departments were cobalt, styrene, and formaldehyde, respectively. A total of 23 different agents were measured. In this study, the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV)-short-term exposure limit (STEL) is used as the health-effect standard for exposure time less than four hours. The ACGIH TLV-TWA (time-weighted average) is used as the standard for exposure times equal to or greater than four hours. The ratio of measured concentrations to the appropriate ACGIH standard was then calculated. The geometric mean of the ratio for the total samples was 0.34 percent of the standards. There were 70 samples from teaching laboratories (geometric mean = 0.38% of the standards), and 62 samples from research laboratories (geometric mean = 0.08% of the standards). The chemical exposures relative to the standards in teaching laboratories were statistically higher than in research laboratories (p-value < 0.001). Information about personal protective equipment and the use of laboratory chemical hoods was also collected. The differences in use of personal protective equipment (PPE) among these departments was not statistically significant. From the air sampling results, we concluded that (1) Chemical exposures in the academic laboratories in this study were all well below the health standards; (2) Undergraduate students in teaching laboratories had higher chemical exposures than graduate students in research laboratories; (3) Chemical exposures among departments were not significantly different; and (4) Hazard communication, safety training, and laboratory rules enforcement are important for protection and may be the reason that the results from this study indicate that chemical exposures in this academic institution are well below the health standards under normal operations.

Storage cabinet for volatile toxic chemicals

It is common practice to store toxic volatile chemicals in a laboratory fume hood. Although this provides safe storage, it becomes necessary to operate the hood continuously, resulting in a continuous loss of conditioned air from the building. Often, bottles containing highly toxic chemicals are few in numbers and small in size so that the storage volume required for this purpose is modest. This makes it possible to utilize a small auxiliary storage cabinet in place of a chemical hood for this purpose, provided all the vapors from the stored chemicals can be retained. We have constructed and tested a passive storage cabinet consisting of a metal box, 30 X 30 X 30 cm, with a front-opening latchable door, a false bottom for catching and retaining liquid spills, and an open top completely covered with a 5-cm depth of tightly packed, gas-adsorbing, activated charcoal. All vapors released inside the cabinet must pass through the charcoal before reaching the outside and are retained on the charcoal. Means are provided to purge the box of residual vapors before opening the door by compressed air line or a hand-operated squeeze bulb. The incoming fresh air sweeps through the chamber and exists through the charcoal filter.

Absence of respiratory effects in subjects exposed to low concentrations of TDI and MDI

One hundred seven subjects from a polyurethane plastic manufacturing plant have been followed over a five-year period with measurements of forced expiratory volume in 1 s (FEV1), and questionnaires on respiratory symptoms and smoking habits. Environmental concentrations of toluene diisocyanate and diphenyl methyl diisocyanate were extensively monitored to provide accurate estimates of the upper-limits of exposure of the subjects. Current mean levels of FEV1 in this population were higher than those predicted for healthy subjects. The five-year change in FEV1 did not exceed that expected from aging. No acute change in FEV1 could be demonstrated over the course of a Monday either before or after a two-week vacation. No improvement in ventilatory function was observed over the vacation period. The presence of cough or sputum was related to smoking but was not related to isocyanate exposure. The results indicate that exposure of workers to extremely low levels of isocyanates (time-weighted average concentrations of the order of 0.001 parts per million [ppm]) is not associated with chronic respiratory symptoms or effects on ventilatory capacity. The results suggest that isocyanates can be controlled to the point of eliminating effects as measured by these techniques.