Regulatory Policy Implications of 1,4-Dioxane - Environmental Investigation and Remediation - page 453

1,4-dioxane in Bray's solution (Beckman Instruments, 1968). The realization that both
TCE and its stabilizer epichlorohydrin had the potential to cause adverse health conse-
quences in the workplace apparently did not extend to evaluating whether solvents and
their stabilizers would cause the degradation of groundwater resources. These late discov-
eries of health effects after chemicals were put into widespread use were not met with a
comprehensive response to address the uncertainty in health effects and risks.
2. Provide adequate long-term environmental and health monitoring and research into early
warnings.
Comment: The occupational health and exposure literature provided evidence of the
lethal consequences of exposure to very high concentrations of 1,4-dioxane well before
1,4-dioxane was employed as a solvent stabilizer (Barber, 1934). By the time that 1,4-dioxane
production was substantially increased to keep up with demand for stabilizing methyl chloro-
form in the 1970s, the toxicology literature on 1,4-dioxane had enough studies to warrant
both health monitoring and further research into the potentially toxic effects of exposure.
However, at that time, governmental agencies had not sufi ciently developed the legal and
administrative framework needed to establish long-term monitoring programs.
3. Identify and work to reduce “blind spots” and gaps in scientii c knowledge.
Comment: A blind spot in the case of 1,4-dioxane introduction to the chemical market-
place as a solvent stabilizer was the lack of recognition of the fact that 1,4-dioxane becomes
concentrated in vapor degreasing operations such that larger quantities of 1,4-dioxane are
included in solvent wastes than are present in the original solvent formulation. In addition,
industry and government personnel may not have fully realized that solvent waste handling
practices such as directing water separator wastes to sewers or sending drummed solvent
wastes to unlined landi lls would cause signii cant groundwater contamination.
4. Identify and reduce interdisciplinary obstacles to learning.
Comment: As discussed in the preceding comment, industrial chemists were not generally
concerned with disposal practices or downstream consequences of solvent stabilizers. On the
one hand, industrial chemists worked with a body of knowledge, chemical engineering, that
is ideally suited to anticipate the environmental fate and transport of solvents and their stabi-
lizers. Industrial chemists certainly knew that the solvent stabilizers were escaping into the
environment because they recommended that fresh solvent should be periodically added
back to the vapor degreaser. They also developed stabilizer concentrates to replenish stabilizers
lost to emissions from open-top vapor degreasers and from removal in water traps and from
disposal of still bottoms. On the other hand, industrial chemists had no direct motivation or
mandate to investigate the potential fate of their chemical inventions in the environment.
Regulators apparently lacked an appreciation for the potential for 1,4-dioxane to become
concentrated in vapor degreaser wastes. For example, a 1996 regulatory staff directive to test
for 1,4-dioxane at California groundwater contamination sites was restricted to known
releases from tanks containing 1,4-dioxane as a pure product. The directive advised the staff
not to require 1,4-dioxane testing at sites with solvent contamination that did not have 1,4-
dioxane tanks to relieve responsible parties from the burden of high analytical costs
(Department of Toxic Substances and Control [DTSC], 1996a.) * Except for the cellulose
acetate membrane i lter industry, polyester manufacturing, and other chemical manufactur-
ing operations that used 1,4-dioxane directly, 1,4-dioxane was not used in sufi ciently high
volumes to justify storage in tanks; therefore, the directive effectively eliminated testing at
vapor degreasing sites, which are likely to have signii cant 1,4-dioxane contamination.
5. Systematically scrutinize the claimed justii cations and benei ts alongside the potential
risks.
* The directive was penned by a political appointee and distributed over the objections of staff scientists at DTSC (Public
Employees for Environmental Responsibility [PEER], 2000).