National Toxicology Program

TR-158
Bioassay of (2-Chloroethyl)trimethylammonium Chloride (CCC) for Possible Carcinogenicity (CAS No. 999-81-5)

(2-Chloroethyl)trimethylammonium chloride is a plant growth regulator, or dwarfing agent, used on poinsettias and azaleas in the United States, and on several food crops, specifically cereal grains, grapes, and pears in Europe.

A bioassay of (2-chloroethyl)trimethylammonium chloride for possible carcinogenicity was conducted by administering the test chemical in feed to F344 rats and B6C3F₁ mice.

Groups of 50 rats of each sex were administered either 1,500 or 3,000 ppm of the compound for 108 weeks, and 50 mice of each sex were administered 500 or 2,000 ppm for 102 weeks. Matched controls consisted of 20 untreated and 20 untreated mice of each sex. All surviving animals were killed at the end of the period of administration of the test chemical.

Mean body weights of dosed rats and mice were lower than those of corresponding controls for part or all of the bioassay, except for the dosed male mice, whose mean body weights were essentially the same as those of the corresponding controls. Survival was not affected significantly in any of the dosed groups of rats or mice and was at least 64% in every dosed or control group of each species at the end of the bioassay. Sufficient numbers of dosed and control rats and mice of each sex were at risk forthe development of late-appearing tumors. Since there was virtually no decrease in mean body weight in dosed male mice and only a slight decrease in female mice, and since there were no other toxic signs and no dose-related mortality, the animals may have been able to tolerate higher doses.

No tumors occurred in the rats or mice of either sex at incidences that could be associated with administration of the test chemical.

It is concluded that under the conditions of this bioassay, (2-chloroethyl)trimethylammonium chloride was not carcinogenic for F344 rats or B6C3F₁ mice of either sex.

Synonyms: Cyclocel®; chlormequat; chlorocholine chloride; CCC

Report Date: 1979

Target Organs from 2-year Studies

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