Understanding the Value ofGlyphosate in Protecting Hawai‘icould not be ruled out. A chart listing othersubstances that are probably carcinogenic to humans,such as very hot beverages and wood fires, is below.

A position presented by the Hawai‘i Invasive Species
Council (HISC) Research and Technology Working
GroupIn 2017, the US Environmental Protection Agency
evaluated the cancer risk of glyphosate to humans inthe Draft Human Health Risk Assessment in Supportof Registration Review. The EPA determined thatglyphosate was “not likely to be carcinogenic tohumans” and supports continuation of current
approved use patterns. So, how could we haveapparently conflicting positions from respectedscientific agencies?

January 2019
The Position
Glyphosate is the active ingredient in many herbicide
formulations registered in the State of Hawai‘i tocontrol non-native weed species in many different
types of environments. Glyphosate-based herbicides
are critical weed management tools that help
maintain profitability in local agriculture, turf andlandscape industries, prevent degradation of our
natural environments, mitigate wildfires throughcreation of firebreaks and control of fire-prone
invasive grasses, and reduce disease vector habitats.
With several decades of regulated use, this pesticide
technology has proven to be one of the most costeffective options in weed control with no historical
reports of environmental or human health impacts in
Hawai‘i. The new Hawai‘i Interagency Biosecurity
Plan (HIBP) provides an ambitious mission toprotect against new and existing biological threats tothe local economy, environment and health of ourisland state. Pesticides, including glyphosate, areintegral technology options for rapid, effectiveinterventions against these threats. We recognize
growing interest by some stakeholders to limit or insome cases ban the use of chemical control options.
Efforts to restrict or ban these tools, however, could
compromise the feasibility of participating agencies
for implementing a well-developed plan to protect
Hawai‘i. We recommend a careful consideration ofrisk and benefits in any future discussions about
policies relating to glyphosate use, and endorse theexpertise within our state and federal agencies
responsible for pesticide regulation.
The Controversy
In 2015, the International Agency for Research on
Cancer (IARC) published an evaluation ofglyphosate categorizing this chemical as “probablycarcinogenic.” The IARC uses this classification
when a positive association has been observed
between exposure to the agent and cancer but otherexplanations for the observations, such as chance,

IARC Evaluations of Selected Products andChemicals
Processed red meat(consumption)
Carcinogenic
Alcoholic beverages
to humans
TobaccoVery hot beverages
Probably
Red meat (consumption)
carcinogenic to
Glyphosatehumans
Biomass fuel (wood fire)
Aloe vera whole leaf extract
Gingko biloba
Possibly
Goldenseal root powder
carcinogenic to
Kava extract
humansRadio frequency
Electromagnetic fields
Hazard vs. Risk
Hazard is defined as a potential source of harm or
adverse health effect on a person, while risk is thelikelihood of harm or adverse health effects due toexposure of the hazard. The IARC Monographs
Program evaluates cancer hazards distinct from
actual risk. This means that the IARC classified
glyphosate as a hazard even though it may beunlikely to cause cancer with current known uses andexposure rates. The EPA conducts risk assessment ofhazard exposures under normal or adverse use
patterns. Therefore, the IARC determination ofhazard and EPA determination of risk may not beconflicting.
Risk Management
Risk management is the process of identification,evaluation, and prioritization of risks, along with theadoption of corresponding measures to minimize thepotential impact due to hazard exposure. Pesticiderisk in Hawai‘i is managed through the registration
and regulation processes administered by the US
EPA in coordination with the Pesticide Branch of theHawai‘i Department of Agriculture. Each registeredpesticide product has a set of vetted guidelines
explicitly stating how, when and where a pesticide
can be applied, as well as how much and by whom.
The product label also describes any protective
equipment or training required for the applicator.
These specified conditions are determined byestablished scientific protocols that aim to minimize
the risk factors to people and the environment. In
addition, the College of Tropical Agriculture andHuman Resources (CTAHR) offers the "Pesticide
Risk Reduction Education" short course foreducating and training professional applicators onproper pesticide stewardship. Any use of a registeredpesticide that is inconsistent with the label
instructions is illegal and punishable by law.
Alternate positions that support the prohibition ofglyphosate potentially undermine the authority andregulatory protocols established by these federal andstate agencies. A ban on glyphosate would also
remove currently irreplaceable tools for combatting
invasive species, creating extreme challenges for
local, state and federal agencies charged withprotecting the unique, fragile ecosystems of Hawai‘i.
Prohibiting effective tools could potentially result in
the irreversible debilitation of our food, water,residential landscapes, and rare native plants andanimals, all of which are heavily impacted byinvasive species. Prohibition of this tool could also
result in increased costs for physical control ofinvasive plants in forests and urban environments.
Pesticides, including herbicides, are technologies
that have greatly benefitted from public andscientific scrutiny over the decades since theirintroduction. Today’s pesticide safety standards anduse guidelines are a direct result of this scrutiny andhelp ensure that the risks associated with exposure
are minimized. When used according to label
instructions, in concert with established integrated
pest management practices, herbicides such as
glyphosate are an invaluable tool in managing
invasive plants.

To learn about the differences between
hazards and risks of glyphosate go to:International Agency for Research on Cancer,
2017. Some organophosphate insecticides andherbicides: tetrachlorvinphos, parathion,
malathion, diazinon and glyphosate. IARC
Working Group. Lyon: IARC Monogr Eval
Carcinog Risk Chem Hum, 112, pp.9-31.
https://monographs.iarc.fr/wpcontent/uploads/2018/07/mono112.pdf
US Environmental Protection Agency. 2017.
Draft Human Health and Ecological Risk
Assessments for Glyphosate.
https://www.epa.gov/ingredients-usedpesticide-products/draft-human-health-andecological-risk-assessments-glyphosate
To learn about the Hawai‘i Interagency
Biosecurity Plan 2017-2027 go to:
Hawai‘i Department of Agriculture:
http://hdoa.hawaii.gov/blog/main/nr1702biosecurityplan/
Hawai‘i Invasive Species Council:
http://dlnr.hawaii.gov/hisc/plans/hibp/
This position paper was prepared by the staff andstakeholders participating in the HISC Research
and Technology Working Group and does not inand of itself reflect a position of the Council.