460 HAZARDOUS WASTES
Hazardous-Waste Characteristics
A waste that falls into one of the lists must still be
examined to determine if it exhibits one or more of these
characteristics: ignitability, corrosivity, reactivity, or toxicity.
If it does, it is considered to represent an additional hazard
and may necessitate special regulatory precautions.Ignitability: Liquid wastes with a flash-point test less
than 60°C and nonliquids that spontaneously catch
fire through friction or by reaction with moisture and
materials that meet the Department of Transportation
definition of an oxidizer
Corrosivity: Aqueous wastes with a pH greater than or
equal to 12.5 or less than or equal to 2, and liquids
that can readily corrode or dissolve flesh, metal, or
other materials (liquids that corrode steel at greater
than 0.25 in. per year at 55°C)
Reactivity: Wastes that readily explode or undergo
violent reactions, for example, sodium hydride
Toxicity: Wastes likely to leach chemicals into
groundwater when discarded, for example, in a
municipal landfillThe EPA designed a procedure called the toxicity char-
acteristic leaching procedure (TCLP) to be used to deter-
mine the leachability of a waste. If the leachate contains
an amount of any of 40 different toxic chemicals above its
regulatory level, the waste is given the waste code associated
with that compound or element.^Excluded Wastes (40 CFR 261.4)Certain wastes have been excluded from hazardous wastes
for practical or economic reasons. Wastes are excluded
because:- They fall within 19 categories that are listed as not
solid wastes - They fall within 17 categories that are listed as not
hazardous wastes - They are regulated under other laws, such as the
Clean Water Act or the Atomic Energy Act - They are generated in laboratory experiments or
waste-treatability studies - They are generated in raw material, product stor-
age, or manufacturing units
Examples:Domestic sewage discharged into a sewer to a munic-
ipal wastewater treatment plant, regulated under the
Clean Water Act
Certain radioactive materials that are regulated by the
Atomic Energy Act
Scrap metal that has been processed to make it easier
to handle
Circuit boards that have been shredded and are free of
potentially dangerous materialsHousehold wastes generated by normal household
activities that could technically be considered
hazardous wastes
Certain wastes from the exploration and production
of oil, gas, and geothermal energy
Treated wood containing hazardous materials such as
arsenic that is discarded by end users
Dredge materials subject to the Marine Protection,
Research, and Sanctuaries Act of 1972Underground Storage Tanks The greatest potential hazard
from underground tanks is leakage that will contaminate
groundwater. The EPA estimates that about 25,000 tanks
out of 2.1 million regulated tanks contain hazardous mate-
rials. In 1984, Congress added Subtitle I to the RCRA to
initiate a program to protect the environment from under-
ground tanks leaking petroleum products and other hazard-
ous materials.
For practical and economic reasons, many tanks are
excluded from meeting federal requirements (but not neces-
sarily state or local):- Tanks of 1,100 gallons or less used to hold motor
fuels for noncommercial purposes on farms and
residences - Tanks for heating oil used on the premises where
tank is stored - Tanks in basements or tunnels
- Septic tanks and storm and wastewater collectors
- Tanks with a capacity of 110 gallons or less
The nature and complexity of the program led the federal
government to allow approved state programs to act in its
place. Inasmuch as state regulations can be more stringent, it
is important that anyone concerned about underground stor-
age tanks be familiar with state requirements. The Petroleum
Equipment Institute Web site presents a map showing which
states regulate tanks; however, it is recommended that your
local regulatory agency be consulted.
LUST, the program for leaking underground storage
tanks, is funded by a 0.1-cent federal tax on every gallon of
motor fuel sold in the country.Accumulated WastesPast practices have left huge quantities of hazardous wastes
deposited in landfills, ponds, fields, and storage in a manner
that threatens our health and environment. Surface and
groundwater supplies of drinking water are especially sen-
sitive to contamination by these accumulations, which can
take thousands of years to clean themselves. Depending on
the type of contamination, treatment may be impractical or
prohibitively expensive.
The federal government response to the problem of
accumulated wastes and emergencies that release haz-
ardous wastes was CERCLA, commonly referred to as
Superfund. This law was enacted by Congress December
11, 1980, and amended by the Superfund Amendments andC008_002_r03.indd 460C008_002_r03.indd 460 11/18/2005 10:29:02 AM11/18/2005 10:29:02 AM