Historical Use of Chlorinated Solvents and Their Stabilizing Compounds - Environmental Investigation and Remediation - page 7

ultrasonic cleaning baths. It reportedly i rst became widely used in the late 1950s as a cold-cleaning
solvent for metal-cleaning applications that previously used carbon tetrachloride, because methyl
chloroform was signii cantly less toxic (HSIA, 1994; Doherty, 2000b). Because of the inherent
chemical instability of methyl chloroform vapors in the presence of aluminum and other alkali
metals, it was not widely used for vapor degreasing until a suitable stabilized vapor-phase formula-
tion became available. As discussed further in Section 1.2.6.6 , the i rst stabilizer that enabled methyl
chloroform use in vapor degreasing of aluminum and other metals was 1,4-dioxane. The addition of
1,4-dioxane to methyl chloroform was i rst patented in 1957 (Bachtel, 1957).
Methyl chloroform was commonly used as a solvent in aerosol formulations and in aerosol pro-
pellant formulations for various household products sold in spray cans. As an aerosol solvent, methyl
chloroform was used to reduce the l ammability of hydrocarbon propellants (HSIA, 1994). A num-
ber of consumer spray aerosol products contained methyl chloroform, including hair sprays, cos-
metics, oven cleaners, spot removers, furniture polishes, automotive lubricants, automotive choke
cleaners, water repellents, and adhesives (Aviado et al., 1976).
Methyl chloroform was promoted by Dow Chemical as a dry-cleaning solvent in the early
1980s. It was used as a primary dry-cleaning solvent (particularly in leather cleaning) by a very
small number of dry-cleaning operations—only 50 plants in the United States. The instability of
methyl chloroform led to problems with machine and equipment corrosion; therefore, it is no lon-
ger used as a dry-cleaning solvent, but is still found in some spot-removal solutions at dry cleaners
that use perchloroethylene, hydrocarbon, or other solvents (Linn et al., 2004). Methyl chloroform
has also been used in spray products to condition suede and for glossing and weatherprooi ng
leather products.
In addition to its major application as a metal cleaner, methyl chloroform was also used in the
following products and processes, among others (World Health Organization, 1990; USEPA, 1994a;
Doherty, 2000a):

• Automotive products

• Coatings and i nishes

• Consumer and industrial adhesives

• Various paints, coatings, and inks

• A textile-scouring agent

• A cleaner for machinery and tools used in the textile industry

•
• An electronics cleaner to remove l ux and dry-i lm photoresist developer from printed cir-
cuit boards
A grease cutter in drain cleaners and septic tank cleaners

A dye carrier

•

• A cleaner for plastic molds

• A pharmaceutical extractant

• A plastic i lm cleaner in the i lm and television industry

• A solvent for various insecticides

• A degreening product for citrus fruits

• A postharvest fumigant for strawberries

• A solvent for natural and synthetic resins, oils, waxes, tars, and alkaloids

• A coolant in cutting oils

• An asphalt-extracting agent for paving aggregate

• A solvent for the application of water and oil repellents to paper and textiles

Methyl chloroform was banned from use as the active ingredient in pesticides in 1998. It was con-
sidered excellent for cleaning plastics, polymers, and resins because it is less likely to degrade these
materials than perchloroethylene or TCE (Tarrer et al., 1989). Tables 1.3 through 1.5 show the end-use
pattern for TCE, perchloroethylene, and methyl chloroform, respectively, for the United States.