Page 57 - Highway Engineering Handbook Building and Rehabilitating the Infrastructure

40 CHAPTER ONE

deteriorating. Life extension and overall protection of the bridges from corrosion are
dependent on refurbishing deteriorating coatings.
The public has become increasingly aware that lead can represent a significant human
health and environmental threat. When intact and in good condition, the paint does not pose
a significant health risk. It is when paint is removed to prepare the surface for coating
replacement, or as the paint deteriorates, that the risk of significant health risks escalates.
Many highway structures are located in urban areas where lead-based paint removal has
the potential to affect adjacent properties and to expose the public to hazardous concentra-
tions of lead. Bridges are often constructed over water bodies where lead-containing dust
from removal operations can affect water quality and the aquatic environment.

1.5.1 Biohazards of Lead

A bioaccumulative substance such as lead can be stored in various organs and tissues of
the body. As lead-containing tissues are consumed by larger organisms in the food
chain, a cumulative effect occurs in each subsequent organism. For example, a fish in a
lead-contaminated environment may be exposed to lead in the water and in the organ-
isms that it eats, which have accumulated lead from their food source, and so on down
the chain. Organisms at the top of the food chain are, therefore, exposed to higher con-
centrations of lead.
In humans, long-term exposure can result in brain and nerve disorders, anemia, elevate
blood pressure, reproductive problems, decreases in red blood cell formation, and slower
reflexes. In high enough doses or after long-term bioaccumulation, lead exposure can cause
death. The Occupational Safety and Health Administration’s (OSHA’s) Interim Final Rule on
Lead Exposure in Construction (29 CFR 1926.62) describes long-term overexposure
effects of lead and provides uniform inspection and compliance guidance for lead exposure
in construction.
The primary methods of exposure to toxic levels of lead are through inhalation and
ingestion. For example, paint removal workers may inhale leaded dust or, in the absence
of proper cleaning and preventative measures, may ingest lead after it has settled on food,
cigarettes, utensils, or other items placed in their mouths.

1.5.2 Regulatory Framework
Hazardous waste is regulated under the RCRA if more than 220 lb (100 kg) of hazardous
waste is generated each month, as is the case in most bridge paint removal projects. RCRA
defines the concentrations of a waste that should be considered hazardous and establishes
procedures for handling and disposing of hazardous waste. Disposing of waste is the
responsibility of the waste generator. The lead-based paint and blasting grit recovered in
bridge paint removal projects may contain concentrations of lead sufficient to classify it as
hazardous, waste in all instances, the owner of the structure is considered the generator (in
some states the contractor removing the paint may be considered a cogenerator). Subtitle C
under RCRA is relevant to lead removal activities. Table 1.11 provides a listing of the per-
tinent RCRA regulations.
Methods of testing wastes to determine whether the waste is hazardous are described in
40 CFR 261. Appendix II of that regulation describes the toxicity characteristic leaching
procedure (TCLP, Method 1311) that must be used to analyze for hazardous constituents
such as lead. Leachable levels of various elements that will establish waste as hazardous
are found in Table 1 of 40 CFR 261.24 and are presented in Table 1.11. Wastes with any
of the characteristics listed in Table 1.12 would be considered hazardous. For example,