It's been a busy week for explosions.  The most amazing feature of this chart is the near-exact conjunction (within one minute of arc or 1/60 of a degree) of the Sun and Mars in Aries, something that hasn't occurred in that sign since April 2, 1981.  On April 11 of that year when the conjunction was still in force but not exact the Brixton riots occurred in London, also accompanied by bombs.  Previous to that conjunctions have occurred in the last century or so in Aries on April 14, 1934 and March 29, 1902 so you can see this combination doesn't come along very often.  The Pluto-Uranus square is undoubtedly a player as well, particularly with Uranus also in fiery Aries along with Mercury and the minor planet, Eris, ruler of discord.  It's interesting that Eris, Uranus, ruler of rebellion and explosions, and Mercury, natural ruler of movement, are all in the 6th house given that the explosion occurred in a place of work.  Jupiter and the asteroid, Chaos, are conjunct in the 8th house of death with Jupiter ruling the 3rd house of neighborhoods and the traditional ruler of the 5th house which includes ego expression and children as well as speculations.

Uranus is also quincunx retrograde Saturn which hints at the extent of rebuilding that will be required to bring this unfortunate town back to normalcy and also suggests the explosive rupture of the huge storage tank.  Sign placement with Uranus in Aries, a highly energetic sign and Saturn in Scorpio, the sign that rules death, carry subtle significance as well. Saturn is at 8 degrees, a critical degree for Fixed signs, giving it additional influence. The Moon is dignified in Cancer squaring Eris, imparting a strong emotional element as well which will extend to the public.  The Moon is also intercepted in Cancer, increasing the emotional component in the 9th house which includes beliefs, expectations, legal matters and academia with implications toward future litigation.  The 10th house is empty which implies this event may not receive that much national publicity, perhaps due to being overshadowed by the Boston Marathon bombing two days before.  The Leo Midheaven is ruled by the Sun but likewise squared by it, hinting at unfortunate news further reinforced by the fact the Sun and Mars are both setting.

Pluto in the 3rd house which includes neighbors is applying to a square with Uranus in the 6th house of work and health, showing the effects of the explosion brought trouble and death to those that lived close to the plant.  Pluto, like the Moon, is intercepted in Capricorn which could indicate hidden problems that contributed to the explosion. Pluto is sextile the asteroid, Chiron, "the wounded healer" which is typically involved in some fashion in disaster charts which involve personal injury.  Neptune, ruler of liquids and chemicals, is sextile Venus, the chart's ruler as well as ruler of the 8th house of death, showing a connection there.  Like Saturn, Neptune is also at a critical degree, this time for a Mutable sign and likewise strengthening its effects. These two planets can also draw compassion and love to this small town as they deal with this disaster.  Neptune is semisextile Mercury in the 6th, an aspect that typically indicates an opportunity that will require effort to pursue.  It can also represent an irritation with Mercury ruling the 9th house of legal matters and beliefs as well as the 11th of groups, friends and goals.  Undoubtedly a host of lawsuits will derive from this incident. Neptune, which also represents delusions, idealism and deception is in the 5th house which includes children as well as speculation, somewhat related to the proximity of the middle school which gratefully was not in session at the time of the explosion.  Apparently whoever decided to locate the school in that location flunked chemistry, especially the concept of exothermic reactions to say nothing of statistics and probability. 

The chart ruler is Venus which is located in the 7th house of relationships and professionals and rules the 12th house of self-undoing and hidden enemies.  A wide opposition to Saturn retrograde suggests structural issues or noncompliances at the plant may be at issue with Saturn ruling the 4th house of home environment as well as endings.  Mercury rules the 9th and 11th houses which has a variety of implications which include the possibility of sabotage or terrorism due to the 9th including belief systems and the 11th, groups, but this is insufficient evidence to be conclusive.  More will undoubtedly come out as the investigation continues but Pluto intercepted and retrograde in Capricorn seems more indicative of hidden problems with the plant infrastructure with the information coming out in the course of the investigation.

Not knowing the time that West was incorporated places strong limitations on comparing the event chart to the city's natal chart.  Thus, the ascendant and Midheaven are not known conclusively or the house placement of the transiting planets at the time so the only reliable interpretation depends on the planetary aspects and signs.  Using a time of noon seems to work with the Sun - Mars conjunction thus situated in the 8th house of death with Jupiter and Chaos on the Midheaven, but this is definitely not to be relied upon no matter how nicely it fits.  West has a rolling sign stellium comprising Mercury, Neptune and Pluto which is being heavily aspected by transiting Saturn and Uranus.  When you consider that Mercury rules movement and work, Neptune rules chemicals, and Pluto covers corruption and hidden problems, triggering this trio certainly had ominous potential, particularly when Uranus, ruler of explosions, is involved along with Saturn retrograde which relates to rebuilding structures among other things.  That alone could easily constitute a huge ka-boom.

The Moon is sextile West's Saturn, again imparting emotion that certainly relates to all the residents rendered homeless by the event.  The explosion chart's ascendant squares West's Chaos, another fitting aspect, with the Sun - Mars conjunction also squaring it to form a T-square of the most ominous kind.  The trine from transiting Jupiter to West's Mars, both in Air signs hints at the explosion and its magnitude as well.

Lacking an accurate chart for the city of West limits the interpretation of this event chart but nonetheless shows substantial ties between malefic planets as well as the asteroid, Chaos, which has certainly earned more respect from this astrologer as a result of this week's literally explosive events.