EPA chose the term "Pollutant" to defined the chemical and infectious
agents in part 503. While EPA and its scientists do talk about pathogens, it
doesn't seemed to be defined except by the Department of Transportartion.
Most of the infectious pathogens in sludge seem to be in the Risk 4 range.
                TITLE 49--TRANSPORTATION


PART 173.134  Class 6, Division 6.2
(a)(1) Division 6.2 (infectious substance) means a material known to
contain or suspected of containing a pathogen. A pathogen is a virus or
micro-organism (including its viruses, plasmids, or other genetic
elements, if any) or a proteinaceous infectious particle (prion) that
has the potential to cause disease in humans or animals. A Division 6.2
material must be assigned to a risk group in accordance with this
paragraph (a). Assignment to a risk group is based on known medical
condition and history of the source patient or animal, endemic local
conditions, symptoms of the source patient or animal, or professional
judgement concerning individual circumstances of the source patient or

(6) Risk group means a ranking of a micro-organism's ability to
cause injury through disease. A risk group is defined by criteria
developed by the World Health Organization (WHO) based on the severity
of the disease caused by the organism, the mode and relative ease of
transmission, the degree of risk to both an individual and a community,
and the reversibility of the disease through the availability of known
and effective preventative agents and treatment. There is no
relationship between a risk group and a packing group. The criteria for
each risk group according to the level of risk are as follows:

                        Risk Group Table
                                                            Risk to           Risk to the
Risk group           Pathogen                 individuals       community
4...............  A pathogen that                    High...........      High.
               usually causes
               serious human or
               animal disease and
               that can be readily
               transmitted from
               one individual to
               another, directly
               or indirectly, and
               for which effective
               treatments and
               preventive measures
               are not usually
3...............  A pathogen that                           High...........     Low.
               usually causes
               serious human or
               animal disease but
               does not ordinarily
               spread from one
               infected individual
               to another, and for
               which effective
               treatments and
               preventive measures
               are available.
2...............  A pathogen that can                   Moderate.......      Low.
               cause human or
               animal disease but
               is unlikely to be a
               serious hazard,
               and, while capable
               of causing serious
               infection on
               exposure, for which
               there are effective
               treatments and
               preventive measures
               available and the
               risk of spread of
               infection is
1...............  A micro-organism      None or very     None or very
               that is unlikely to   low.             low.
               cause human or
               animal disease. A
               material containing
               only such micro-
               organisms is not
               subject to the
               requirements of
               this subchapter.