ernment takes immediate action. In >dye tests with a simple bacterial its report the panel urges removal assay system he has developed over of price controls and associated the past 10 years, using special regulations from petroleum and strains of Salmonella typhimurium natural gas, deregulation of the and rat or human microsomal en wellhead price of new natural gas, zymes. Together with Dr. Harold and large and frequent lease acreage O. Kammen and Edith Yamasaki, sales on the outer continental shelf. Ames has tested 169 different According to the panel, nuclear "permanent" oxidative-type dye energy is the only nonfossil energy formulations—"all the products we source increased use of which can could find in two local drugstores." make an impact during the next 10 Of these, 150 were mutagens in the to 15 years. The panel says the gov bacterial assay. ernment should simplify licensing Commercial hair colorants con of nuclear power plants. tain various combinations of 18 dif In R&D the panel recommends ferent aromatic oxidative dye com that the federal government: pounds, mainly amines, diamines, • Assume primary responsibility and/or phenols. Nine of the 18, for funding long-term, high-risk tested individually, were mutagens programs, including breeder reac in the assay, with 2,4-diaminotors, solar energy, and fusion pro anisole the most active. (Other, structurally similar aromatic grams. • Increase funding for programs amines are known carcinogens, related to improved coal mining, Ames notes.) The question is whether Ames' coal conversion and utilization, ad vanced power generation methods, hair dye bacterial results can be ex radioactive waste disposal, and trapolated to man. Ames points out energy-related public health effects. that proven carcinogens show a high • Provide assistance for construc correlation with mutagenicity in his tion and operation of at least one system. oil shale, two coal gasification, and Definite proof can come only two coal liquefaction commercial- from long-term tests on animals or scale demonstration plants. from epidemiological studies. The panel sees the competitive Clairol's Menkart says that many market place as the best way to long-term animal tests already have achieve allocation and conservation been done and that they clear all of energy resources. It advocates, dye compounds now in use. Epi among other things, an increase in demiological data available to date the investment tax credit to 10% are "reassuring," he adds. (2,4per year for all industries and an Diaminotoluene was shown carcino increase in allowed tax depreciation genic in one study and withdrawn rates to 5% per year for long-life from hair dye use in 1970. It shows capital investments. G mutagenicity in Ames' test.) Ames replies that most of the compounds formed by oxidative colorants and dyes present in nonoxidative colorants have not been tested for carcinogenicity. Further more, studies done so far have been "grossly inadequate." Controversy is brewing about Animal tests are under way at the chemicals in another consumer National Cancer Institute and in product. This time the target is hair industry. One NCI test has been dyes used by 20 million to 25 million completed : m -Phenylenediamine, Americans ($250 million annual weakly mutagenic by Ames' test, sales). shows no long-term carcinogenicity There is "high probability ,, that when fed to rats and mice. G some hair colorants may cause can cer, says Dr. Bruce N. Ames of the University of California, Berkeley, in a paper to be published in the Proceedings of the National Acade my of Sciences. (Ames is an NAS member and expert on mutagens and bacterial biochemical genetics.) The estimated 200 million rats in Not so, retorts Dr. John Menkart, the U.S. and untold millions world vice president-technology of Clairol wide got some bad news last week Inc. There is "no evidence that hair when Rohm & Haas took the wraps dyes are unsafe," says Menkart, off its new Vacor rodenticide. An also chairman of the scientific ad acute toxicant that kills in one visory committee of the Cosmetic, feeding, the product will make its Toiletry, & Fragrance Association. market debut April 1. Ames' charges are based on hair Significantly, says the Philadel-
Hair dyes focus of latest cancer scare
Rat poison does deed in only one feeding
8
C&EN March 24, 1975
Vacor kills warfarin-resistant rats
phia-based chemical maker, Vacor kills even the so-called "super rats," rats that have developed re sistance to warfarin, an anticoagu lant and the most common rodenti cide. Warfarin kills over a period of several days by causing internal hemorrhaging. Vacor kills in four to eight hours after ingestion of a sin gle dose of as little as 0.5 gram. Warfarin requires that a rat feed on it from three to 10 days. According to Rohm & Haas pres ident Vincent L. Gregory, the new product is expected to add about $1.00 per share in earnings within five years, "and we're sure we are going to get it." In 1974 earnings per share were $5.83. Rohm & Haas stresses that Vacor is specific for the most common ro dent pests, including the Norwe gian (brown) rat, the roof (grey) rat, and the house mouse. It is rela tively safe for other animals and humans, the company asserts. Chemically iV-3-pyridylmethyl-iV'-p-nitrophenyl urea, the com pound will be marketed as a 2% mixture with a grain substrate, and as a 10% powder. It kills by inhibit ing niacinamide metabolism, and the rats eventually die from paraly sis and pulmonary arrest. Warfarin resistance, although in creasingly common in the U.S., is still not a major problem. The New York City Health Department says that 90 to 95% of the estimated 8 million rats loose in the city are still susceptible to the chemical. However, this number may be de clining because rats are able to pass resistance along to offspring, and they have about four litters per year. Recently, the city has been trying out a British product, Calciferol, a brand of vitamin D 2 , that kills even warfarin-resistant rats by produc ing hypercalcemia. Like warfarin, however, Calciferol requires multi ple feedings to be effective. α
