History

Pemaco is a former chemical mixing facility located in a light industrial and residential area at 5050 Slauson Boulevard, Maywood, CA. It is believed that Pemaco began on-site operations in the late 1940s. Pemaco was purchased by the LUX Chemical Company on July 27, 1988, and operations ended at the site on June 21, 1991. Hazardous substances are known to have been used at the facility, including chlorinated solvents, aromatic solvents, and flammable liquids.

Shortly after the closure of the facility, the Los Angeles County Hazardous Materials (Hazmat) Unit ordered the potentially responsible party to remove containers and drums of laboratory chemicals located in the warehouse and outside staging area. However in December 1993, the facility burned to the ground. Although the fire completely destroyed the warehouse, six 55-gallon drums, several above-ground storage tanks, and thirty-one underground storage tanks were unaffected by the fire. Due to safety concerns after the fire, the Environmental Protection Agency was asked to conduct an emergency assessment and stabilize the site. The Agency responded by doing the following: 1) erecting a chain link fence with razor wire around the site; 2) verifying that all storage tanks were empty; 3) attaching locking caps to standpipes; and 4) removing a small number of 55-gallon drums for disposal. Having completed site stabilization activities, EPA referred the site back to the LA County Hazmat and informed the EPA Site Assessment program about the site for further study. After further studies to define the nature and extent of contamination, and initiation of cleanup activities, the site was placed on the Superfund

Superfund

Superfund is the common name for the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 , a United States federal law designed to clean up sites contaminated with hazardous substances...

 National Priorities List

National Priorities List

The National Priorities List is the list of hazardous waste sites in the United States eligible for long-term remedial action financed under the federal Superfund program. Environmental Protection Agency regulations outline a formal process for assessing hazardous waste sites and placing them on...

 on January 19, 1999.

Contaminant and Risks

During the initial assessment study at Pemaco, the EPA found high levels of Volatile Organic Compounds (VOCs) in the soil beneath the site. The groundwater beneath the site was also contaminated with VOCs. VOCs at the site included: Perchloroethylene (PCE), Trichloroethylene

Trichloroethylene

The chemical compound trichloroethylene is a chlorinated hydrocarbon commonly used as an industrial solvent. It is a clear non-flammable liquid with a sweet smell. It should not be confused with the similar 1,1,1-trichloroethane, which is commonly known as chlorothene.The IUPAC name is...

 (TCE), Trichloroethane

Trichloroethane

Trichloroethane can refer to either of two isomeric chemical compounds:* 1,1,1-Trichloroethane * 1,1,2-Trichloroethane...

 (TCA), Dichloroethane

Dichloroethane

Dichloroethane can refer to either of two isomeric organochlorides with the molecular formula C2H4Cl2:* 1,1-Dichloroethane * 1,2-Dichloroethane...

 (DCA) and vinyl chloride

Vinyl chloride

Vinyl chloride is the organochloride with the formula H2C:CHCl. It is also called vinyl chloride monomer, VCM or chloroethene. This colorless compound is an important industrial chemical chiefly used to produce the polymer polyvinyl chloride . At ambient pressure and temperature, vinyl chloride...

 (VC). VOCs are known or suspected carcinogens and, therefore, could have posed a serious risk to neighbors if they were exposed to the chemicals.

Facility records indicate that the following materials were stored in tanks: methanol

Methanol

Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...

, ethanol

Ethanol

Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...

, xylene

Xylene

Xylene encompasses three isomers of dimethylbenzene. The isomers are distinguished by the designations ortho- , meta- , and para- , which specify to which carbon atoms the two methyl groups are attached...

, propylene glycol

Propylene glycol

Propylene glycol, also called 1,2-propanediol or propane-1,2-diol, is an organic compound with formula C3H8O2 or HO-CH2-CHOH-CH3...

, 2-ethoxyethyl acetate, isopropyl acetate

Isopropyl acetate

Isopropyl acetate is an ester, an organic compound which is the product of condensation of acetic acid and isopropanol. It is a clear, colorless liquid with a characteristic fruity odor....

, isophorone

Isophorone

Isophorone is an α,β-Unsaturated cyclic ketone, a colorless to yellowish liquid with characteristic smell, that is used as a solvent and as an intermediate in organic synthesis...

, ethyl acetate

Ethyl acetate

Ethyl acetate is the organic compound with the formula CH3COOCH2CH3. This colorless liquid has a characteristic sweet smell and is used in glues, nail polish removers, and cigarettes...

, butanol

Butanol

Butanol or butyl alcohol can refer to any of the four isomeric alcohols of formula C4H9OH:*n-Butanol, butan-1-ol, 1-butanol, n-butyl alcohol;*Isobutanol, 2-methylpropan-1-ol, isobutyl alcohol;...

, kerosene

Kerosene

Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...

, tolusol, hexane

Hexane

Hexane is a hydrocarbon with the chemical formula C6H14; that is, an alkane with six carbon atoms.The term may refer to any of four other structural isomers with that formula, or to a mixture of them. In the IUPAC nomenclature, however, hexane is the unbranched isomer ; the other four structures...

, ispropanol, 2-butanone, 2-butoxy ethanol, toluene

Toluene

Toluene, formerly known as toluol, is a clear, water-insoluble liquid with the typical smell of paint thinners. It is a mono-substituted benzene derivative, i.e., one in which a single hydrogen atom from the benzene molecule has been replaced by a univalent group, in this case CH3.It is an aromatic...

, acetone

Acetone

Acetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...

, and unleaded gasoline.

These compounds can have health affects on infants or very young children. It has been reported that “respiratory, allergic, or immune effects in infants or children” are associated with indoor VOCs and other indoor air pollutants. It is suggested that VOC particles in an indoor environment can be reduced by 50% when household rugs and carpets are cleaned with efficient vacuum cleaners and hot water. These chemicals can also cause nausea, vomiting, diarrhea, permanent blindness, deterioration of the central nervous system, neurological side effects, and in some cases may be cancerous or fatal.

Investigation and Clean Up

In 1998, the EPA selected soil vapor extraction to clean up soils left behind after excavating the underground storage tanks. Commonly used throughout the country, soil vapor extraction removes vapors from the soil, then treats them with a thermal oxidation system. The treatment system burned the vapors as they passed through a heated system. The system included automatic safeguards to shut down in the event of malfunction, and it was tested to guarantee that emissions were within limits required by County, State and Federal Agencies.

The filter and thermal heating system worked as follows: 1) the soil gas passed through a filter system where a majority of contaminants were captured on filter material; 2) the unfiltered contaminants in the soil gas were then treated in a heated chamber that broke down the contaminants at temperatures exceeding 1,400 degrees F.

During incineration, most of the contaminants were reduced to non-toxic compounds, such as carbon dioxide and water. In 1998, the EPA collected weekly data on VOCs going into and coming out of the incinerator. The air at the fence line was sampled weekly to verify that no VOCs were leaving the site. EPA turned off the system later in 1998, because the sampling program did not measure potential dioxin emissions. However, based on tests of similar systems used on other projects, it is believed that emissions of VOCs, dioxins and other chemicals were low and did not pose an elevated threat to public health.

The Record of Decision for the Pemaco site was signed on January 13, 2005. Construction of the final remedy began during 2005. EPA completed construction of the remedy that was included in the Maywood Riverfront Park by June 2006. Construction of the treatment plant and placement of the equipment into the treatment plant continued until early 2007. EPA turned on the groundwater treatment system during April 2007. The vapor recovery and treatment system was turned on during May 2007, and Electrical resistance heating remediation

Electrical resistance heating remediation

Electrical Resistance Heating is an intensive in situ environmental remediation method that uses the flow of alternating current electricity to heat soil and groundwater and evaporate contaminants. Electric current is passed through a targeted soil volume between subsurface electrode elements...

for the source area of the site began full operations during September 2007. EPA turned off the Electrical Resistive Heating remedy during April 2008 and permanently transferred vapor treatment over to carbon during June 2008. The concentrations in the ERH area, vapor treatment system and groundwater continue to decrease over time.

CleanUp Results

Since it was safe to develop the Pemaco property during construction of the treatment system, the City of Maywood began construction of the Maywood Riverfront Park during August 2005. The Maywood Riverfront Park is now complete and part of the Los Angeles River Greenway Project. The park opened in May 2008. EPA completed construction of the treatment system in the summer of 2006.