Those old "tootsie rolls" are indeed part of the San Jacinto Ordinance Depot, which used to cover the entire area from Penn City Road east and I-10/Dezavalla Road south to the Houston Ship Channel. It was built right after Pearl Harbor along with a few others around the country, as I've been told 60 miles out of Galveston Bay because the longest missile range at the time was 40-50 miles. Those structures are old munition storage bunkers, which are spaced evenly along parallel concrete roads running northeast and southwest from Jacintoport Boulevard (you can still see these quite well from above if you look at Google Maps or another satellite mapping website). All of the ones I bothered to poke my head into were completely empty save a piece or two of debris (surprising since many of them are completely surrounded by debris and dumped junk).
This is what the inside looks like, if anyone is curious:
The SJOD apparently closed down in the 1960s and much of the land there is still vacant. There's still dozens of the bunkers out there on private land, though, as you can see below, and some have been converted by local industries for their own use and fitted with garage doors! (sorry, I don't have any pics of that.)
Information on the internet about the SJOD is scarce. There are some informative posts on another older string on this forum at http://www.houstonarchitecture.info/haif/i...amp;#entry75717 or Houston Architecture Info Forum - HAIF