From e-mail: Four questions: What degree of variation is there in the Dallas area regarding municipal ordinances for hazardous materials storage? How effectively are such regulations being enforced (e.g. conducting inspections, requiring permits, inventories)? Which community has most effectively addressed hazardous materials storage and industrial zoning? Which community needs the most improvement in these areas?

Michael Grabell: The issue of hazardous chemicals near residential neighborhoods is certainly something that almost every city deals with. One issue that Dallas officials discovered after the Southwest Industrial Gases explosion was that the hazardous use regulations required a special permit only for plants that make hazardous chemicals. It doesn’t include those that store, distribute or use the chemicals to make other products. As far as inspections go, the Dallas fire marshal’s office is supposed to inspect sites with hazardous materials annually. But with limited resources, it’s typically once ever few years. I’m told inspectors focus first on schools, night clubs, apartments, anything that’s deemed to have a "high risk of lives lost" if there were to be a fire. In addition, buildings like hospitals, day cares and hotels are required to have a fire inspection to renew their license. So there’s a backlog of sites with hazardous materials.

From e-mail: Did you ever think that the chemical plants were there long before the people moved into the area? Did you think that the plant should just pick-up and move because the people were too dumb to buy around a chemical plant?

Michael Grabell: Yes, this is one of the things we pointed out in the story. In most cases, the plants were there first and the homes came later. What our story really focused on was how and why the homes, schools and apartments were built near plants with hazardous chemicals. In nearly every case, the residents had no idea the plants had hazardous chemicals, even if they had lived near the plant for 50+ years because they were never told about it. Many of the plants don’t have telltale smokestacks and few have sent information to the neighbors informing them of the risk. Check out the last story, in which we tried to address things that other cities have done. It’s not as easy as telling a plant that has been there for years to move.

From e-mail: We all drive around with a virtual 10- to 15-gallon bomb behind the back seat of our cars when we leave the gas station. Perhaps most alarming is that these threats are totally unregulated by government. Seriously, the threat of massive devastation from chemicals is slight and well-regulated by state and federal agencies. Granted, some money-hungry corporations might push local operators to take the risk, but that's why we have agencies like OSHA, TCEQ and ultimately the courts to adjudicate punishment for neglecting safety. The reporter might have a point when he notes that some plants are across the street from schools or homes. He notes that debris from a downtown fire and explosion was thrown a quarter-mile. (No one was killed.) Is there a spot in Dallas where we could relocate all such industry with a half-mile to one-mile perimeter of vacant land? Or maybe we should just send these companies packing (with their jobs and tax revenue) some place far away.

Michael Grabell: This is a good point. I hope the story didn’t come off as “the 10 things in your house that can kill you!!” While hazards are all around us, these plants pose far greater risk than the 10 to 15 gallon gas tanks in our cars. As to the question of a spot where Dallas could relocate all such industry, there is a significant amount of vacant land in southeast Dallas, near where Interstate 45 crosses with Loop 12 and I-20. The city is trying to develop an industrial down there as well as an already industrial district to the northwest along Interstate 35 near Royal Lane.

TXRick: Agreed w/Michael on the last question. When we moved here, we had NO idea that we lived near a plant which stored toxic chemicals. Nope, no smokestack, no warning signs on the building, no mention on the internet, etc.... and our builder certainly didn't disclose this to us... Question - Michael, did you look at the rail transport of toxic chemicals through our neighborhoods to/from these plants and elsewhere? That seems to me to be at least as big a threat. Or the proximity of these plants with flammables to the gas pipelines? Thanks for a great series...

Michael Grabell: TXRick, thanks for your message. While rail transport wasn't the focus of our series, the rail cars are just as much of a threat when they're traveling by railroad as they are when they're at the plant. Some say they're even more of an issue because of the risks associated of moving them. This the focus of much debate right now in Washington with efforts to reroute hazardous materials around heavily populated metropolitan areas. Also, check out this link: http://www.pe.com/digitalextra/metro/trains/. Our sister paper, the Riverside Press-Enterprise, did a big series about the dangers of hazardous materials transported by rail in southern California.

From e-mail: I was just wondering how many homes were built near the plants after the plant was originally built? Were the homes there first or the plants? How were the plants or houses able to have been built so close considering the restrictions placed by city zoning laws?

Michael Grabell: In many cases, the plants were built first and the homes came later. The zoning restrictions and philosophies have adapted over time as cities learned more and more about the risks posed by hazardous chemicals. Some of the situations were created by a old company town model of 100 years ago while others were created by the more modern desire to revitalize an old industrial area that still has plants with hazardous chemicals in it. Others are hidden hazards. For example, a water treatment plant or a dairy doesn’t seem as dangerous as a chemical plant with a big smokestack; so residents, developers, even city officials, might not necessarily realize the risk when homes start moving closer to the site.

Michael Grabell: Mann, welcome to the room. TXRick, what neighborhood do you live in?

TXRick: Thanks for your reply Michael, I'm checking out the rail info link... One other question if you dont mind - what about these gas pipelines that run through our neighborhoods? Are they sufficiently shielded/safe as to not be a cause for concen? I recall the foiled terror plot at JFK airport which was said to put at risk a large part of the entire boro of Queens if their pipeline had been ignited. Scary stuff...

Michael Grabell: TXRick, I haven't looked as deeply into gas pipelines so can't say for sure how shielded/safe/regulated they are. We've certainly had a few incidents in D-FW in the last few years. One place to check that out is http://phmsa.dot.gov/. Also, did you see the series that Brett Shipp over at Channel 8 did last year? If I can find it, I'll post a link.

TXRick: In Las Colinas we have one of the chemical companies listed in the report, a nearby Exxon storage area, buried gas pipelines and trains which likely carry toxic/flammable chemicals...

Michael Grabell: Right. I think Mohawk Labs is over there. The key for all of these issues it to look at what chemicals/materials are stored there and how close your home is to them. Based on my research, I believe Mohawk was about a little less than a 1/2 mile from a neighborhood. You can find out more by requesting to view their risk management plan at the EPA office downtown. Here's a link on how to do that: http://www.epa.gov/osweroe1/content/rmp/#accessing. For plants that don't have risk management plans, search on the EPA and OSHA's Web site for the the plants near you.

TXRick: Thanks Michael - will look for Brett's report and at the PHMSA site... appreciate all your good work.. thanks...

Michael Grabell: Here's a link to Brett's stories on the gas leak danger:

Michael Grabell: http://www.wfaa.com/bshipp/. Scroll to the bottom.

Michael Grabell: Thanks for your questions. If you have any more, feel free to e-mail me at mgrabell@dallasnews.com.