Note: Pseudonym sources: Roger Robinson (his source: McGhan), Contento/Locus. Note that ISFDB lists Peter Cartur as a pseudonym for Peter Grainger. However, the copyright/acknowledgments for Fifty Short Science Fiction Tales includes:

Peter Cartur The Mist. Copyright 1952 by Fantasy House, Inc. Reprinted by permission of Forrest J. Ackerman.

Usually something like this would indicate that Peter Cartur is a pseudonym as copyrights need to be filed under the author's real name. It's not known if Forrest J. Ackerman bought the rights to this story or if Peter Cartur is one of Forrest J. Ackerman's pseudonyms.