NON-TOXIC TO ANIMAL LIFE

When a dust control agent is applied to roadways, or other dusty areas, there is often a concern about its effect on the wildlife in the vicinity, as well as on the humans applying and working with the material. This is also a concern to Pennzoil, and one that was considered when formulating PennzSuppress^® D.

The toxicity of a substance when ingested is known as its oral toxicity, which is expressed in terms of its LD₅₀ value. "LD₅₀," which stands for lethal dose 50%, indicates the amount of a material that must be consumed to kill 50% of the test animal population in a controlled study. The higher the LD₅₀ value, the greater the amount of material the test animals can tolerate, hence the lower the toxicity of the test material.

To estimate the effect of consumption of PennzSuppress^® D by humans applying the product or animals living near a treated area, an acute oral toxicity test was performed by feeding the concentrated product (a "worst-case" scenario) to white rats. An LD₅₀ value of >30,000 mg/kg was obtained, indicating that the road dust suppressant is essentially non-toxic. Since the product is not used in its concentrated form, water dilutions would be even less of a concern. To put this in perspective, the oral LD₅₀ of several common materials are listed below, along with the result of the PennzSuppress^® D concentrate (remember - the higher the value, the lower the toxicity):

NON-IRRITATING TO EYES

To estimate the effect of spraying PennzSuppress^® D into the eyes of humans applying the product, or animals in the area, a Primary Eye Irritation Test was performed using the concentrated product. The dust suppressant was evaluated as having a Toxicity Category of “IV,” and no adverse eye reactions were noted at any time during the study. This indicates that PennzSuppress^® D is essentially non-irritating to the eye. Since the product is not applied in its concentrated form, but is diluted significantly with water, the diluted product would be of even less concern.

NON-CARCINOGENIC

None of the components of PennzSuppress^® D are classified as carcinogens according to OSHA, IARC, or NTP, therefore the road dust suppressant is considered to be non-carcinogenic.

PennzSuppress^® D is partially composed of a vacuum residuum. Since some vacuum residua contain asphaltenes, which are often the subjects of concern as to potential carcinogenicity, further discussion is warranted. It is important to note that vacuum residuum produced by Pennzoil’s Rouseville, Pennsylvania refinery is different than other vacuum residua, in that it does not contain asphaltenes, due to the unique characteristics of its originating crude. To determine the carcinogenic potential of vacuum residua, the American Petroleum Institute (API) conducted lifetime skin painting studies and short-term tumor initiation/promotion assays in mice. This testing showed negative activity in both assays, therefore it was concluded that the vacuum residuum partially composing PennzSuppress^® D is not carcinogenic.

Some of the specific potential carcinogens in unprocessed lubricating oils, which could be found in petroleum resins, are polynuclear aromatic hydrocarbons (PNA's). Analyses of Pennzoil resin show it to contain no carcinogenic PNA’s, further supporting the conclusion that the resin in PennzSuppress^® D is not carcinogenic.

NON-MUTAGENIC

The term "mutagen" generally refers to a substance which causes mutations, or a change in the genetic material of cells. Unlike carcinogens, mutagens can be detected in short-term tests which can be run in bacteria, cultured cells (in vitro) or in whole animals (in vivo). When the API tested vacuum residua in the in vivo bone marrow cytogenetics assay in rats, the residua were non-mutagenic. In this test, animals are dosed with the test substance, and their bone marrow cells are examined for chromosomal damage. Similarly, vacuum residua were non-mutagenic in the in vitro mouse lymphoma assay. In this assay, the test material is mixed directly with mouse lymphoma cells in culture, and mutations are scored. If the vacuum residuum was first digested with rat liver enzymes, and then mixed with mouse lymphoma cells in culture, it was weakly mutagenic. When the results of all tests are evaluated collectively, the vacuum residuum, such as that used in the formulation of PennzSuppress^® D, is considered non-mutagenic.