Impact of Revised Airborne Exposure Limits on Non-Stockpile Chemical Materiel Program Activities (2005)

The alarm points for the MINICAMS monitoring airborne VX concentrations at the Newport Chemical Depot (NECD) will not be changed after January 1, 2005. Since the committee agrees that the new airborne exposure limits (AELs) can be implemented for VX at the NECD facility demolition project without changing the MINICAMS alarm level, no increase in the number or frequency of MINICAMS alarms is expected. The Product Manager for Non-Stockpile Chemical Materiel (PMNSCM) has also demonstrated to the committee that VX at concentrations equal to the worker population limit (WPL) can be detected using the depot area air monitoring system (DAAMS) for VX. Therefore, the new AELs do not necessitate any process changes for demolition activities at the VX former production facility at NECD.

As described in Chapter 2, the explosive destruction system (EDS) and the rapid response system (RRS) share many features, such as the use of MINICAMS and DAAMS monitors for near-real-time and confirmatory/historical monitoring, respectively. As summarized from Chapter 2 in Table 5-1, both systems provide primary and secondary control of agent vapor emissions.

In both systems, it is assumed that the primary containment area becomes contaminated during the processing of munitions but that this contamination is reduced or eliminated by decontamination procedures. Progress in decontaminating the explosion containment vessel or glove boxes is monitored following agent neutralization. The vapors in the primary containments are vented through multiple activated-carbon beds.

In both systems, all process vapor emissions are passed through activated carbon and monitored before being released to the ambient environment. In effect, the carbon bed exhaust monitors serve as perimeter monitors. However, as discussed in Chapter 2, more remote perimeter monitors are deployed when the EDS is operated in proximity to a civilian population.

The impact of the new AELs will be most pronounced for the EDS, which is used to destroy munitions containing H/HD/HT, GB, and VX as well as some of the less common blister and choking agents. Because there are believed to be no chemical agent identification sets (CAIS) containing nerve agents still in existence, the main impact on RRS operations will be during the processing of mustard agents.

The EDS has processed and will continue to process a variety of munitions and agent-filled containers holding both blister and nerve agents—primarily H/HD and GB and occasionally VX. Existing equipment should be able to monitor at the worker population limits (WPLs) and short-term exposure limits (STELs) listed by the Centers for Disease Control and Prevention (CDC) for these agents (see Figures 4-1 through 4-3), although using DAAMS to monitor at the new WPLs may be time consuming and expensive, especially if numerous DAAMS samples must be collected and analyzed in order to have confidence that the new WPLs are not exceeded. A requirement to obtain and analyze several (rather than one) DAAMS samples each day for the purpose of determining whether or not the WPL has been exceeded is expected to adversely impact worker productivity, especially if normal daily operations are interrupted as a consequence of the retrieval and analysis of DAAMS tubes. Costs will also increase owing to the need for additional monitoring and analysis staff, monitoring equipment, and analytical capabilities.

Expenses incurred as a result of monitoring at the new AELs will also increase if state regulators require that MINICAMS alarm set points and DAAMS reportable limits are set at some percentage of the new AELs. Even if these values fall within the certification ranges of the monitors,

the frequency of NRT alarms due to the detection of interferents is expected to increase, as will the need to obtain and analyze DAAMS tubes to confirm the alarms.

If state regulators require lower alarm set points (for MINICAMS) and reportable limits (for DAAMS)—for example, at 50 percent or 20 percent of the AELs—then the probability of false positives due to the detection of interferents will increase further. Moreover, these alarm set points and reportable limits might be below the lower ends of the current certification ranges for MINICAMS and DAAMS monitors, respectively. This is discussed on an agent-specific basis next.

For the blister agent mustard (H and HD, for example), the 15-minute STEL will be the same as the 1988 time-weighted average (TWA) of 3 × 10⁻³ mg/m³, which is well within the monitoring capabilities of MINICAMS (Federal Register, 2003b). The new 8-hour WPL will be 4 × 10⁻⁴ mg/m³ and is measurable with DAAMS tubes. If, in the worst case, some states require that the alarm set point for the MINICAMS be 0.20 STEL (or 6 × 10⁻⁴ mg/m³), this will still be within the certification range for MINICAMS, but the incidence of false positives and their associated costs will increase. If states require that the DAAMS reportable limit for the 8-hour WPL be a fraction of the WPL, for example, 0.50 WPL (or 2 × 10⁻⁴ mg/m³), this will be within the current certification range for DAAMS under the current version of the Programmatic Laboratory and Monitoring Quality Assurance Program (U.S. Army, 2004f).

Finding 5-1: To summarize, it should be technically possible for the Army to continue to monitor as at present under the new AELs for HD. However, both cost and schedule impacts are expected, depending in part on the MINICAMS alarm set points and the DAAMS reportable limits that are used.

For GB, the 15-minute STEL will be 1 × 10⁻⁴ mg/m³, well within the MINICAMS capability. The new WPL will be 3 × 10⁻⁵ mg/m³, also within DAAMS capabilities (Federal Register, 2003a). Alarm set points for the MINICAMS that are as low as 20 percent of the STEL will fall within the certification range for MINICAMS shown in Figure 4-1, although the probability of alarming due to interferents will increase, along with cost and schedule impacts. DAAMS monitors having a reportable limit as low as 20 percent of the WPL—6 × 10⁻⁶ mg/m³—should be able to detect at this level since this is at the lower end of the current DAAMS certification range for GB.

Finding 5-2: If the Army is required to monitor at the GB WPL—at 3 × 10⁻⁵ mg/m³—then it may be possible to use MINICAMS for this purpose rather than DAAMS monitors since this is slightly above the lower limit of the MINICAMS certification range and would provide near-real-time WPL monitoring.

PMNSCM hopes to use monitoring levels and alarm set points that are consistent with the level of PPE that is used. For example, in its final Programmatic Monitoring Concept Plan (U.S. Army, 2004g), the Army gives 8-hour WPLs and 15-minute STELs that are up to four orders of magnitude higher than those for unprotected workers, depending on the degree of worker protection. If PMNSCM were to take credit for PPE and to use the correspondingly higher WPLs and STELs, then MINICAMS alarm set points and DAAMS reportable limits that are even a small fraction of these values will fall well within the certification ranges of existing monitoring equipment. Using GB as an example, the 8-hour WPL for unprotected workers is 3 × 10⁻⁵ mg/m³, but for workers using air-purifying respirators (Level C PPE), the 8-hour WPL, in effect, increases 50-fold, to 1.5 × 10⁻³ mg/m³ (U.S. Army, 2004g).¹

The EDS may be used to process non-stockpile items containing VX. For VX, the 15-minute STEL will be 1 × 10⁻⁵ mg/m³, within the capability of MINICAMS, although moni-

toring at this level at NECD has resulted in false positives caused by phosphorus-containing compounds. The new WPL will be 1 × 10⁻⁶ mg/m³, within the capability of DAAMS monitors (see Figure 4-2). If however, states require that the MINICAMS alarm set point be at a low fraction of the 15-minute STEL—for example, at 2 × 10⁻⁶ mg/m³—then this is close to the lower end of the VX certification range for MINICAMS (see Figure 4-2) and it may not be possible for MINICAMS to reliably distinguish between VX and interferents at this level. As a result, the number of MINICAMS alarms is expected to increase, along with the number of confirming DAAMS tubes to be analyzed. Higher fractional alarm set points for VX—5 × 10⁻⁶ mg/m³—will, however, fall within the MINICAMS certification range and are expected to result in fewer false positive MINICAMS alarms.

Also, low fractional reportable limits for DAAMS—for example, 2 × 10⁻⁷ mg/m³, or 20 percent of the new WPL—will present problems in confirmation monitoring since the lower end of the certification range for VX using DAAMS monitors is on the order of 6 × 10⁻⁷ mg/m³, as shown in Figure 4-2.

In summary, although both MINICAMS and DAAMS are capable of monitoring at the new STELS and WPLs, respectively, it would be helpful if the use of PPE were taken into consideration when the MINICAMS alarm set points and DAAMS reportable limits are selected, as noted in Recommendation 2-4. If credit for the use of PPE cannot be taken, then fractional MINICAMS alarm set points and DAAMS reportable limits are expected to be set that do not require the monitors to alarm at agent concentrations below the lower ends of their certification ranges.

RRS operations will be largely unaffected by the new AEL standards. The primary impact of the new AELs will occur when the RRS is processing CAIS items containing sulfur mustard agent. Based on the Pine Bluff Arsenal environmental assessment for the destruction of CAIS sets (U.S. Army, 2003c), at least 83 percent of the items contain H or HD; the total might exceed 90 percent.

In considering the impact of the new AELs, the requirement for NRT monitoring at the 15-minute STEL should be largely unaffected because the new target is approximately equivalent to the 1988 TWA of 3 × 10⁻³ mg/m³. Because the current MINICAMS monitors meet this target routinely, implementing this new requirement should present few challenges other than modest changes in recordkeeping, instrument maintenance, and operator training.² For a mobile system such as the RRS, which will operate in many different environments, instrument maintenance may be especially important. Similarly, measurements at the newly defined immediately dangerous to life and health (IDLH) level of 0.7 mg/m³ are within the capability of the MINICAMS. Confirmatory and historical monitoring of H/HD concentrations at the STEL level using DAAMS tubes should also be accomplished readily.

Monitoring for sulfur mustard at the new WPL of 4 × 10⁻⁴ mg/m³ is more challenging. This concentration is below the level routinely accessible with the MINICAMS but well within the capability of the DAAMS, which will be analyzed daily to monitor worker exposures relative to the WPL. Since an 8-hour TWA is necessarily retrospective, the delayed response while a DAAMS sample is acquired and the adsorbate in the DAAMS tube is analyzed does not seem to pose a technical problem. The main problematic aspect that will require remediation concerns personnel who discover that they have been exposed to agent at levels above the WPL during the preceding shift.

Because the RRS will be used at military facilities and the limited quantities of agent do not pose a significant risk to any civilian population, there appears to be no reason to institute perimeter monitoring for RRS operations. Hence, it is unlikely that there will be any need to monitor at the new GPL. To monitor at the new GPL of 2 × 10⁻⁵ mg/m³ would require significant development work on the DAAMS operating protocol.

Finding 5-3: There appears to be no reason to institute perimeter monitoring for RRS operations.

The Army used the 1988 AELs to determine whether certain types of materials posed a further hazard to workers (e.g., contaminated tools, contaminated buildings) and to implement management systems for secondary waste, much of which is defined as hazardous waste under federal and state hazardous waste laws. Known as the X Classification System, these standards determine decontamination requirements and define subsequent management procedures. The old X Classification System is contained in Department of the Army pamphlet (DA PAM) 385-61 (U.S. Army, 2002). Under this DA PAM, the decontamination status of possibly agent-contaminated materiel is defined as follows:

• 1X (X) indicates that a material or waste has been partially decontaminated but needs further treatment before it can be shipped or handled without special arrangements for worker protection.

• 3X (XXX) is applied to materials or waste that have been surface-decontaminated such that they do not produce a vapor concentration in excess of the agent-specific AEL for an unmasked worker (the old TWA). Many provisos

apply, but 3X materials or wastes can generally be handled or shipped as long as they remain under government control. For example, wastes may be sent off-site for treatment and/or disposal in government or commercial permitted RCRA waste treatment, storage, and disposal facilities (TSDFs).

• 5X (XXXXX) indicates that the materiel or waste is decontaminated completely of the indicated agent. The only approved 5X decontamination (DA PAM 385-61) protocol is thermal treatment at a minimum of 1000°F (538°C) for a minimum of 15 minutes. 5X materials may be released from government control and disposed of as nonhazardous waste or may be sold as scrap to the general public.

The Army is planning to revise DA PAM 385-61, as well as the regulation on which it is based, to incorporate the new AELs. In addition, the Army has indicated (U.S. Army, 2004b, 2004g) that not only will it replace the 1988 AELs with the new 2003/2004 AELs for purposes of material and waste classification, but it will also substantially revise the X Classification System. Because the X Classification System defines management systems for secondary waste, including hazardous waste management systems, these standards have been incorporated into all regulatory approval and permitting (RAP) documents established for non-stockpile (and stockpile) operations. Hence, RAP requirements pertaining to waste management requirements will have to be modified to incorporate the new requirements.

The Army has indicated that the modification of the X Classification System for decontamination is the most controversial aspect of the whole AEL implementation process and that the main stockpile demilitarization sites have already reported long schedule delays due to the required permit changes.³ Considering the potential for continuing delays, changing RAP documents to incorporate the new material and waste management systems is a critical path regulatory issue.

The committee observes that the issues involved cut across all of the Army’s chemical programs. The impact on the non-stockpile program is relatively minor in comparison with the impacts on the stockpile programs. In particular, the committee believes that an examination of the X Classification System under the new AELs is worthy of a more comprehensive evaluation as part of a larger study. It has therefore decided not to further examine the subject in this report. The provisions outlined in the Implementation Guidance Policy (U.S. Army, 2004b) and in the Programmatic Monitoring Concept Plan (U.S. Army, 2004g) may change as the requirements are clarified.⁴